CVE-2026-59822: in the CISA KEV catalogue
BerriAI LiteLLM Improper Authentication Vulnerability. CISA added CVE-2026-59822 to the Known Exploited Vulnerabilities catalogue on 2026-09-02 with a default due date of 2026-09-16. Known ransomware campaign use: Unknown. Forensic triage flag: No.
BerriAI LiteLLM contains an improper authentication vulnerability in the MCP Streamable HTTP endpoint that could allow an unauthenticated attacker to establish an authenticated MCP session using an arbitrary Bearer token. (CISA description)
- Vendor / product
- BerriAI LiteLLM
- CWE
- CWE-287, CWE-306
- 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
- 0.84%, percentile 57 (scored 2026-11-03)
EPSS puts about 8.4 in 1,000 odds (0.84%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 57% of scored CVEs. Most CVEs score under 1%, so a high percentile can sit on a small probability: read the percentage first.
Vendor and reference links (from CISA)
- https://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q
- 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-2026-59822
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-2026-59822 in the CISA KEV catalogue?
Yes. CISA added CVE-2026-59822 (BerriAI LiteLLM Improper Authentication Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2026-09-02. CISA's default due date for it is 2026-09-16.
Is CVE-2026-59822 used in ransomware attacks?
CISA marks known ransomware campaign use as Unknown for CVE-2026-59822. That means CISA lacks confirmation, not that ransomware groups do not use it.
What should I do about CVE-2026-59822?
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-2026-59822