CVE-2026-20127: in the CISA KEV catalogue
Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability. CISA added CVE-2026-20127 to the Known Exploited Vulnerabilities catalogue on 2026-02-25 with a default due date of 2026-02-27. Known ransomware campaign use: Unknown. Forensic triage flag: No.
Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, and Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, contain an authentication bypass vulnerability could allow an unauthenticated, remote attacker to bypass authentication and obtain administrative privileges on an affected system. This vulnerability exists because the peering authentication mechanism in an affected system is not working properly. An attacker could exploit this vulnerability by sending crafted requests to an affected system. A successful exploit could allow the attacker to log in to an affected Cisco Catalyst SD-WAN Controller as an internal, high-privileged, non-root user account. Using this account, the attacker could access NETCONF, which would then allow the attacker to manipulate network configuration for the SD-WAN fabric. (CISA description)
- Vendor / product
- Cisco Catalyst SD-WAN Controller and Manager
- CWE
- CWE-287
- CISA required action
- Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlines in CISA’s Emergency Directive 26-03 (URL listed below in Notes) and CISA’s “Hunt & Hardening Guidance for Cisco SD-WAN Devices (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.
- EPSS
- 89%, percentile 99 (scored 2026-11-03)
EPSS puts about 89 in 100 odds (89%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 99% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.
Vendor and reference links (from CISA)
- https://www.cisa.gov/news-events/directives/ed-26-03-mitigate-vulnerabilities-cisco-sd-wan-systems
- https://www.cisa.gov/news-events/directives/supplemental-direction-ed-26-03-hunt-and-hardening-guidance-cisco-sd-wan-systems
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa-EHchtZk
- https://nvd.nist.gov/vuln/detail/CVE-2026-20127
Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.
Frequently asked questions
Is CVE-2026-20127 in the CISA KEV catalogue?
Yes. CISA added CVE-2026-20127 (Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2026-02-25. CISA's default due date for it is 2026-02-27.
Is CVE-2026-20127 used in ransomware attacks?
CISA marks known ransomware campaign use as Unknown for CVE-2026-20127. That means CISA lacks confirmation, not that ransomware groups do not use it.
What should I do about CVE-2026-20127?
CISA's required action: Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlines in CISA’s Emergency Directive 26-03 (URL listed below in Notes) and CISA’s “Hunt & Hardening Guidance for Cisco SD-WAN Devices (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.
Sources
- CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
- FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
- NVD record for CVE-2026-20127