CVE-2026-18577: in the CISA KEV catalogue
N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability. CISA added CVE-2026-18577 to the Known Exploited Vulnerabilities catalogue on 2026-08-03 with a default due date of 2026-08-06. Known ransomware campaign use: Unknown. Forensic triage flag: Yes.
N-able N-central contains an authentication bypass using an alternate path or channel allows for authentication bypass and account takeover in N-central. This vulnerability is the result of an incomplete patch for CVE-2026-18556. (CISA description)
- Vendor / product
- N-able N-central
- CWE
- CWE-288
- CISA required action
- Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- EPSS
- 15%, percentile 96 (scored 2026-11-03)
EPSS puts about 15 in 100 odds (15%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 96% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.
Vendor and reference links (from CISA)
- https://documentation.n-able.com/N-central/Release_Notes/GA/Content/N-central_2026.3_HF1_Release_Notes.htm
- https://status.n-able.com/2026/08/02/n-central-2026-3-hotfix-1-mitigation-for-cve-2026-18577/
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-18577
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-2026-18577 in the CISA KEV catalogue?
Yes. CISA added CVE-2026-18577 (N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2026-08-03. CISA's default due date for it is 2026-08-06.
Is CVE-2026-18577 used in ransomware attacks?
CISA marks known ransomware campaign use as Unknown for CVE-2026-18577. That means CISA lacks confirmation, not that ransomware groups do not use it.
What should I do about CVE-2026-18577?
CISA's required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
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-2026-18577