What happened
CISA added CVE-2026-59822 affecting BerriAI LiteLLM to its Known Exploited Vulnerabilities catalog on September 2, 2026.
CISA vulnerability name: BerriAI LiteLLM Improper Authentication Vulnerability
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.
Why it matters
Inclusion in CISA’s KEV catalog means the vulnerability has met CISA’s criteria for known exploitation in the wild. That makes it a higher-priority remediation signal than a vulnerability that is only theoretically exploitable.
CWE: CWE-287, CWE-306
What you should do
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.
CISA remediation due date for federal civilian agencies: September 16, 2026.
Additional CISA notes
https://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: 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