CVSS 3.0 Calculator
The CVSS 3.0 calculator scores a CVSS:3.0 vector with the equations of the v3.0 specification. The Base score uses the same equations as v3.1: ISS from the Confidentiality, Integrity and Availability weights, Impact, Exploitability (8.22 × AV × AC × PR × UI) and a round-up to one decimal place. Temporal and Environmental scores follow the same structure.
Two things differ from v3.1 and are implemented as the v3.0 document defines them: the Modified Impact formula (exponent 15 on [ISC_Modified − 0.02], with no 0.9731 factor) and the definition of "Round up", which v3.1 later pinned down with an integer method. A CVSS:3.0 vector is therefore never scored with the v3.1 equations here.
CVSS v3.0 score 9.8, Critical, CVSS-B
- Base
- 9.8
Load a worked example
A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI…
Specialized access conditions or extenuating circumstances do not exist.
The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
The vulnerable system can be exploited without interaction from any user.
An exploited vulnerability can only affect resources managed by the same authority.
There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker.
There is a total loss of integrity, or a complete loss of protection.
There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is…
Assigning this value to the metric will not influence the score.
>Assigning this value to the metric will not influence the score.
Assigning this value to the metric will not influence the score.
Assigning this value to the metric will not influence the score.
Assigning this value to the metric will not influence the score.
Assigning this value to the metric will not influence the score.
Not Defined: the corresponding Base metric value is used (this is the default).
Not Defined: the corresponding Base metric value is used (this is the default).
Not Defined: the corresponding Base metric value is used (this is the default).
Not Defined: the corresponding Base metric value is used (this is the default).
Not Defined: the corresponding Base metric value is used (this is the default).
Not Defined: the corresponding Base metric value is used (this is the default).
Not Defined: the corresponding Base metric value is used (this is the default).
Not Defined: the corresponding Base metric value is used (this is the default).
How this score was computed
Result
- Score to publish
9.8 (CVSS-B)Base score.
Base score
- Impact Sub-Score (ISS)
1 − [(1 − C) × (1 − I) × (1 − A)]1 − [(1 − 0.56) × (1 − 0.56) × (1 − 0.56)] = 0.9148 - Impact (Scope Unchanged)
6.42 × ISS6.42 × 0.9148 = 5.8731 - Exploitability
8.22 × AV × AC × PR × UI8.22 × 0.85 × 0.77 × 0.85 × 0.85 = 3.887 - Base score
Round up(Minimum[Impact + Exploitability, 10])Round up(min(9.7602, 10)) = Round up(9.7602) = 9.8
Scoring runs in your browser; nothing you enter is uploaded. Independent implementation of the FIRST.org CVSS v3.0 specification; CVSS is owned by FIRST.org, Inc. Severity scale: None 0.0, Low 0.1–3.9, Medium 4.0–6.9, High 7.0–8.9, Critical 9.0–10.0.
TL;DRWhat this calculator does
4 points
- Base score equations are identical in v3.0 and v3.1; Environmental scores differ when Modified Scope is Changed.
- v3.0 Modified Impact (scope changed) = 7.52 × [ISC_Modified − 0.029] − 3.25 × [ISC_Modified − 0.02]^15.
- v3.0 defines "Round up" as the smallest one-decimal number equal to or higher than its input; the integer method of v3.1 Appendix A is not part of v3.0.
- Severity scale: None 0.0, Low 0.1 to 3.9, Medium 4.0 to 6.9, High 7.0 to 8.9 and Critical 9.0 to 10.0.
CVSS 3.0 equations
From section 8 of the CVSS v3.0 Specification Document:
ISS = 1 − [(1 − Confidentiality) × (1 − Integrity) × (1 − Availability)]Impact = 6.42 × ISS (Scope Unchanged); 7.52 × (ISS − 0.029) − 3.25 × (ISS − 0.02)^15 (Scope Changed)Exploitability = 8.22 × AttackVector × AttackComplexity × PrivilegesRequired × UserInteractionBaseScore = 0 if Impact ≤ 0; otherwise Round up(min(Impact + Exploitability, 10)), or Round up(min(1.08 × (Impact + Exploitability), 10)) if Scope is ChangedTemporalScore = Round up(BaseScore × ExploitCodeMaturity × RemediationLevel × ReportConfidence)ISC_Modified = min(1 − [(1 − CR × MC) × (1 − IR × MI) × (1 − AR × MA)], 0.915)ModifiedImpact = 6.42 × ISC_Modified (Modified Scope Unchanged); 7.52 × [ISC_Modified − 0.029] − 3.25 × [ISC_Modified − 0.02]^15 (Changed)ModifiedExploitability = 8.22 × MAV × MAC × MPR × MUIEnvironmentalScore = 0 if ModifiedImpact ≤ 0; otherwise Round up(Round up(min([1.08 ×] (ModifiedImpact + ModifiedExploitability), 10)) × E × RL × RC)Round up is defined in the v3.0 document as the smallest number, specified to one decimal place, that is equal to or higher than its input; v3.1 later added an integer-based method in its Appendix A. The Modified Impact formula above (exponent 15, no 0.9731 factor) is the v3.0 formula and differs from v3.1.
Weights used (Table 16 of the specification):
| Metric | Weights |
|---|---|
| Attack Vector (AV) | Network 0.85, Adjacent Network 0.62, Local 0.55, Physical 0.2 |
| Attack Complexity (AC) | Low 0.77, High 0.44 |
| Privileges Required (PR) | None 0.85; Low 0.62 (0.68 if Scope is Changed); High 0.27 (0.5 if Scope is Changed) |
| User Interaction (UI) | None 0.85, Required 0.62 |
| Confidentiality / Integrity / Availability | High 0.56, Low 0.22, None 0 |
| Exploit Code Maturity (E) | Not Defined 1, High 1, Functional 0.97, Proof-of-Concept 0.94, Unproven 0.91 |
| Remediation Level (RL) | Not Defined 1, Unavailable 1, Workaround 0.97, Temporary Fix 0.96, Official Fix 0.95 |
| Report Confidence (RC) | Not Defined 1, Confirmed 1, Reasonable 0.96, Unknown 0.92 |
| Security Requirements (CR, IR, AR) | Not Defined 1, High 1.5, Medium 1, Low 0.5 |
CVSS 3.0 metrics explained
Descriptions are excerpted from the CVSS v3.0 Specification Document. Each metric has a vector abbreviation (in brackets) that appears in the vector string.
Base metrics · 8 metrics
Intrinsic qualities of the vulnerability that stay constant over time and across environments. Usually set by the vendor or advisory.
Attack Vector (AV)
This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the Base score) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable component.
- Network (AV:N) — A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed "remotely exploitable" and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).
- Adjacent Network (AV:A) — A vulnerability exploitable with adjacent network access means the vulnerable component is bound to the network stack, however the attack is limited to the same shared physical (e.g. Bluetooth, IEEE 802.11), or logical (e.g. local IP subnet) network, and cannot be performed across an OSI layer 3 boundary (e.g. a router). An example of an Adjacent attack would be an ARP (IPv) or neighbor discovery (IPv) flood leading to a denial of service on the local LAN segment. See also CVE 2013 6014.
- Local (AV:L) — A vulnerability exploitable with Local access means that the vulnerable component is not bound to the network stack, and the attacker's path is via read/write/execute capabilities. In some cases, the attacker may be logged in locally in order to exploit the vulnerability, otherwise, she may rely on User Interaction to execute a malicious file.
- Physical (AV:P) — A vulnerability exploitable with Physical access requires the attacker to physically touch or manipulate the vulnerable component. Physical interaction may be brief (e.g. evil maid attack [1]) or persistent. An example of such an attack is a cold boot attack which allows an attacker to access to disk encryption keys after gaining physical access to the system, or peripheral attacks such as Firewire/USB Direct Memory Access attacks.
Attack Complexity (AC)
This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability. As described below, such conditions may require the collection of more information about the target, the presence of certain system configuration settings, or computational exceptions.
- Low (AC:L) — Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
- High (AC:H) — A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may depend on an attacker overcoming any of the following conditions: - The attacker must conduct target-specific reconnaissance.
Privileges Required (PR)
This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability. This metric is greatest if no privileges are required.
- None (PR:N) — The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
- Low (PR:L) — The attacker is authorized with (i.e. requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
- High (PR:H) — The attacker is authorized with (i.e. requires) privileges that provide significant (e.g. administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction (UI)
This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
- None (UI:N) — The vulnerable system can be exploited without interaction from any user.
- Required (UI:R) — Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator.
Scope (S)
An important property captured by CVSS v.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges. This consequence is represented by the metric Authorization Scope, or simply Scope.
- Unchanged (S:U) — An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.
- Changed (S:C) — An exploited vulnerability can affect resources beyond the authorization privileges intended by the vulnerable component. In this case the vulnerable component and the impacted component are different.
Confidentiality (C)
This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
- High (C:H) — There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
- Low (C:L) — There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is constrained. The information disclosure does not cause a direct, serious loss to the impacted component.
- None (C:N) — There is no loss of confidentiality within the impacted component.
Integrity (I)
This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.
- High (I:H) — There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
- Low (I:L) — Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is constrained. The data modification does not have a direct, serious impact on the impacted component.
- None (I:N) — There is no loss of integrity within the impacted component.
Availability (A)
This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the impacted component, this metric refers to the loss of availability of the impacted component itself, such as a networked service…
- High (A:H) — There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed).
- Low (A:L) — There is reduced performance or interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.
- None (A:N) — There is no impact to availability within the impacted component.
Temporal metrics · 3 metrics
Characteristics that change over time, such as exploit code and available fixes. Optional.
Exploit Code Maturity (E)
This metric measures the likelihood of the vulnerability being attacked, and is typically based on the current state of exploit techniques, exploit code availability, or active, "in-the-wild" exploitation. Public availability of easy-to-use exploit code increases the number of potential attackers by including those who are unskilled, thereby increasing the severity of the vulnerability.
- Not Defined (E:X) — Assigning this value to the metric will not influence the score. It is a signal to a scoring equation to skip this metric.
- High (E:H) — Functional autonomous code exists, or no exploit is required (manual trigger) and details are widely available. Exploit code works in every situation, or is actively being delivered via an autonomous agent (such as a worm or virus). Network-connected systems are likely to encounter scanning or exploitation attempts. Exploit development has reached the level of reliable, widely-available, easy-to-use automated tools.
- Functional (E:F) — Functional exploit code is available. The code works in most situations where the vulnerability exists.
- Proof-of-Concept (E:P) — Proof-of-concept exploit code is available, or an attack demonstration is not practical for most systems. The code or technique is not functional in all situations and may require substantial modification by a skilled attacker.
- Unproven (E:U) — No exploit code is available, or an exploit is theoretical.
Remediation Level (RL)
The Remediation Level of a vulnerability is an important factor for prioritization. The typical vulnerability is unpatched when initially published. Workarounds or hotfixes may offer interim remediation until an official patch or upgrade is issued.
- Not Defined (RL:X) — >Assigning this value to the metric will not influence the score. It is a signal to a scoring equation to skip this metric.
- Unavailable (RL:U) — There is either no solution available or it is impossible to apply.
- Workaround (RL:W) — There is an unofficial, non-vendor solution available. In some cases, users of the affected technology will create a patch of their own or provide steps to work around or otherwise mitigate the vulnerability.
- Temporary Fix (RL:T) — There is an official but temporary fix available. This includes instances where the vendor issues a temporary hotfix, tool, or workaround.
- Official Fix (RL:O) — A complete vendor solution is available. Either the vendor has issued an official patch, or an upgrade is available.
Report Confidence (RC)
This metric measures the degree of confidence in the existence of the vulnerability and the credibility of the known technical details. Sometimes only the existence of vulnerabilities are publicized, but without specific details. For example, an impact may be recognized as undesirable, but the root cause may not be known.
- Not Defined (RC:X) — Assigning this value to the metric will not influence the score. It is a signal to a scoring equation to skip this metric.
- Confirmed (RC:C) — Detailed reports exist, or functional reproduction is possible (functional exploits may provide this). Source code is available to independently verify the assertions of the research, or the author or vendor of the affected code has confirmed the presence of the vulnerability.
- Reasonable (RC:R) — Significant details are published, but researchers either do not have full confidence in the root cause, or do not have access to source code to fully confirm all of the interactions that may lead to the result. Reasonable confidence exists, however, that the bug is reproducible and at least one impact is able to be verified (proof-of-concept exploits may provide this).
- Unknown (RC:U) — There are reports of impacts that indicate a vulnerability is present. The reports indicate that the cause of the vulnerability is unknown, or reports may differ on the cause or impacts of the vulnerability. Reporters are uncertain of the true nature of the vulnerability, and there is little confidence in the validity of the reports or whether a static Base score can be applied given the differences described.
Environmental metrics · 11 metrics
Characteristics unique to your environment: how much each of confidentiality, integrity and availability matters, and Base values you override. Set by the organisation that deploys the product. Optional.
Confidentiality Requirement (CR)
These metrics enable the consumer to customize the score depending on the importance of the affected IT asset to the analyst’s organization, measured in terms of confidentiality, integrity, and availability.
- Not Defined (CR:X) — Assigning this value to the metric will not influence the score. It is a signal to the equation to skip this metric.
- High (CR:H) — Loss of [Confidentiality / Integrity / Availability] is likely to have a catastrophic adverse effect on the organization or individuals associated with the organization (e.g., employees, customers).
- Medium (CR:M) — Loss of [Confidentiality / Integrity / Availability] is likely to have a serious adverse effect on the organization or individuals associated with the organization (e.g., employees, customers).
- Low (CR:L) — Loss of [Confidentiality / Integrity / Availability] is likely to have only a limited adverse effect on the organization or individuals associated with the organization (e.g., employees, customers).
Integrity Requirement (IR)
These metrics enable the consumer to customize the score depending on the importance of the affected IT asset to the analyst’s organization, measured in terms of confidentiality, integrity, and availability.
- Not Defined (IR:X) — Assigning this value to the metric will not influence the score. It is a signal to the equation to skip this metric.
- High (IR:H) — Loss of [Confidentiality / Integrity / Availability] is likely to have a catastrophic adverse effect on the organization or individuals associated with the organization (e.g., employees, customers).
- Medium (IR:M) — Loss of [Confidentiality / Integrity / Availability] is likely to have a serious adverse effect on the organization or individuals associated with the organization (e.g., employees, customers).
- Low (IR:L) — Loss of [Confidentiality / Integrity / Availability] is likely to have only a limited adverse effect on the organization or individuals associated with the organization (e.g., employees, customers).
Availability Requirement (AR)
These metrics enable the consumer to customize the score depending on the importance of the affected IT asset to the analyst’s organization, measured in terms of confidentiality, integrity, and availability.
- Not Defined (AR:X) — Assigning this value to the metric will not influence the score. It is a signal to the equation to skip this metric.
- High (AR:H) — Loss of [Confidentiality / Integrity / Availability] is likely to have a catastrophic adverse effect on the organization or individuals associated with the organization (e.g., employees, customers).
- Medium (AR:M) — Loss of [Confidentiality / Integrity / Availability] is likely to have a serious adverse effect on the organization or individuals associated with the organization (e.g., employees, customers).
- Low (AR:L) — Loss of [Confidentiality / Integrity / Availability] is likely to have only a limited adverse effect on the organization or individuals associated with the organization (e.g., employees, customers).
Modified Attack Vector (MAV)
Modified version of the Base metric "Attack Vector". It lets you override the Base value for your own environment. This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the Base score) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable component.
- Not Defined (MAV:X) — Not Defined: the corresponding Base metric value is used (this is the default).
- Network (MAV:N) — A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed "remotely exploitable" and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).
- Adjacent Network (MAV:A) — A vulnerability exploitable with adjacent network access means the vulnerable component is bound to the network stack, however the attack is limited to the same shared physical (e.g. Bluetooth, IEEE 802.11), or logical (e.g. local IP subnet) network, and cannot be performed across an OSI layer 3 boundary (e.g. a router). An example of an Adjacent attack would be an ARP (IPv) or neighbor discovery (IPv) flood leading to a denial of service on the local LAN segment. See also CVE 2013 6014.
- Local (MAV:L) — A vulnerability exploitable with Local access means that the vulnerable component is not bound to the network stack, and the attacker's path is via read/write/execute capabilities. In some cases, the attacker may be logged in locally in order to exploit the vulnerability, otherwise, she may rely on User Interaction to execute a malicious file.
- Physical (MAV:P) — A vulnerability exploitable with Physical access requires the attacker to physically touch or manipulate the vulnerable component. Physical interaction may be brief (e.g. evil maid attack [1]) or persistent. An example of such an attack is a cold boot attack which allows an attacker to access to disk encryption keys after gaining physical access to the system, or peripheral attacks such as Firewire/USB Direct Memory Access attacks.
Modified Attack Complexity (MAC)
Modified version of the Base metric "Attack Complexity". It lets you override the Base value for your own environment. This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability. As described below, such conditions may require the collection of more information about the target, the presence of certain system configuration settings, or computational exceptions.
- Not Defined (MAC:X) — Not Defined: the corresponding Base metric value is used (this is the default).
- Low (MAC:L) — Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
- High (MAC:H) — A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may depend on an attacker overcoming any of the following conditions: - The attacker must conduct target-specific reconnaissance.
Modified Privileges Required (MPR)
Modified version of the Base metric "Privileges Required". It lets you override the Base value for your own environment. This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability. This metric is greatest if no privileges are required.
- Not Defined (MPR:X) — Not Defined: the corresponding Base metric value is used (this is the default).
- None (MPR:N) — The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
- Low (MPR:L) — The attacker is authorized with (i.e. requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
- High (MPR:H) — The attacker is authorized with (i.e. requires) privileges that provide significant (e.g. administrative) control over the vulnerable component that could affect component-wide settings and files.
Modified User Interaction (MUI)
Modified version of the Base metric "User Interaction". It lets you override the Base value for your own environment. This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
- Not Defined (MUI:X) — Not Defined: the corresponding Base metric value is used (this is the default).
- None (MUI:N) — The vulnerable system can be exploited without interaction from any user.
- Required (MUI:R) — Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator.
Modified Scope (MS)
Modified version of the Base metric "Scope". It lets you override the Base value for your own environment. An important property captured by CVSS v.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges. This consequence is represented by the metric Authorization Scope, or simply Scope.
- Not Defined (MS:X) — Not Defined: the corresponding Base metric value is used (this is the default).
- Unchanged (MS:U) — An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.
- Changed (MS:C) — An exploited vulnerability can affect resources beyond the authorization privileges intended by the vulnerable component. In this case the vulnerable component and the impacted component are different.
Modified Confidentiality (MC)
Modified version of the Base metric "Confidentiality". It lets you override the Base value for your own environment. This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
- Not Defined (MC:X) — Not Defined: the corresponding Base metric value is used (this is the default).
- High (MC:H) — There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
- Low (MC:L) — There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is constrained. The information disclosure does not cause a direct, serious loss to the impacted component.
- None (MC:N) — There is no loss of confidentiality within the impacted component.
Modified Integrity (MI)
Modified version of the Base metric "Integrity". It lets you override the Base value for your own environment. This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.
- Not Defined (MI:X) — Not Defined: the corresponding Base metric value is used (this is the default).
- High (MI:H) — There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
- Low (MI:L) — Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is constrained. The data modification does not have a direct, serious impact on the impacted component.
- None (MI:N) — There is no loss of integrity within the impacted component.
Modified Availability (MA)
Modified version of the Base metric "Availability". It lets you override the Base value for your own environment. This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the impacted component, this metric refers to the loss of availability of the impacted component itself, such as a networked service…
- Not Defined (MA:X) — Not Defined: the corresponding Base metric value is used (this is the default).
- High (MA:H) — There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed).
- Low (MA:L) — There is reduced performance or interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.
- None (MA:N) — There is no impact to availability within the impacted component.
CVSS 3.0 severity ratings
The qualitative severity rating scale in the CVSS 3.0 specification (use is optional):
| Rating | CVSS score |
|---|---|
| None | 0.0 |
| Low | 0.1 – 3.9 |
| Medium | 4.0 – 6.9 |
| High | 7.0 – 8.9 |
| Critical | 9.0 – 10.0 |
Worked CVSS 3.0 examples
Use “Load a worked example” in the calculator to open any of these. Scores are computed live by the same engine.
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HA CVSS:3.0 vector as published by FIRST (v4.0 Examples page, Panasonic Control FPWIN example).
Source: FIRST CVSS v4.0 Examples page.
Open in the calculatorCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HThe v3.0 Base equations match v3.1, so Base-only vectors score the same.
Source: FIRST CVSS v3.1 User Guide examples / v4.0 Examples page.
Open in the calculatorCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/CR:H/IR:H/AR:H/MAV:L/MS:C/MC:H/MI:H/MA:HModified Scope Changed uses (ISC_Modified − 0.02)^15 in v3.0; the same metrics under CVSS:3.1 score 9.4.
Source: Computed from the v3.0 and v3.1 specification equations.
Open in the calculatorCVSS v3.0 vs v3.1
The metrics and Base equations are the same. The v3.1 specification changes the Modified Impact formula used for the Environmental score when Modified Scope is Changed (exponent 13 with MISS × 0.9731, where v3.0 used exponent 15) and adds Appendix A, an integer method for Roundup. Open the CVSS 3.1 calculator to score the same metrics under v3.1.
Frequently asked questions
What is the CVSS 3.0 calculator and how is the score computed?
It scores CVSS:3.0 vectors with the v3.0 specification equations. ISCBase = 1 − [(1 − C) × (1 − I) × (1 − A)]. Impact is 6.42 × ISCBase when Scope is Unchanged, or 7.52 × [ISCBase − 0.029] − 3.25 × [ISCBase − 0.02]^15 when Changed. Exploitability is 8.22 × AV × AC × PR × UI. The Base score is 0 if Impact is 0 or less, otherwise the rounded-up minimum of (Impact + Exploitability) and 10, with a 1.08 multiplier when Scope is Changed.
How is CVSS 3.0 different from CVSS 3.1?
The metrics are the same. The v3.1 specification states that the exponent at the end of the Modified Impact sub-formula is 13 in v3.1, which differs from v3.0 (15, with no 0.9731 factor), so Environmental scores can differ when Modified Scope is Changed. v3.1 also adds Appendix A, an integer-based definition of Roundup to avoid floating-point errors. Use the v3.0 engine for CVSS:3.0 vectors and the v3.1 engine for CVSS:3.1 vectors.
Why does the same vector score differently in CVSS 3.0 and 3.1?
Only when Environmental metrics are used with Modified Scope Changed. For example, the Environmental vector in the "Where v3.0 and v3.1 differ" example below scores 9.3 under CVSS:3.0 and 9.4 under CVSS:3.1 because of the different Modified Impact formula. Base scores for the same Base metrics match.
What is the CVSS 3.0 severity scale?
The v3.0 specification maps scores to None 0.0, Low 0.1 to 3.9, Medium 4.0 to 6.9, High 7.0 to 8.9 and Critical 9.0 to 10.0. The scale is the same in v3.1 and v4.0.
What does a CVSS 3.0 vector look like?
It begins with CVSS:3.0, for example CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N. Metrics may be written in a non-preferred order, as the specification's own example CVSS:3.0/S:U/AV:N/AC:L/PR:H/UI:N/C:L/I:L/A:N/E:F/RL:X shows; all Base metrics are required and omitted Temporal and Environmental metrics are Not Defined.
When should I use the CVSS 3.0 calculator instead of 3.1?
When the record you are checking carries a CVSS:3.0 vector, for instance an older advisory, so that your result matches the version the vector was published in. For new assessments, score in the version your process requires.
Sources and official calculators
Official calculators: FIRST CVSS v3.0 calculator · NVD CVSS v3 calculator
CVSS is a trademark of FIRST.org, Inc. This calculator is an independent implementation of the published specifications and is not affiliated with FIRST or NIST. Specification text and examples were read on 3 November 2026.