What is CVE-2026-59822?
LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.84.0, LiteLLM's MCP Streamable HTTP endpoint allowed an unauthenticated attacker to use a fabricated Authorization header to trigger an OAuth2 passthrough fallback path that replaced failed LiteLLM key validation with an empty UserAPIKeyAuth() object, allowing requests to reach MCP tooling without a valid LiteLLM key. This issue is fixed in version 1.84.0.
Timeline
- 2026-07-08Published to the U.S. National Vulnerability Database (NVD)
- 2026-09-02Added to the CISA Known Exploited Vulnerabilities (KEV) catalog
- 2026-09-03NVD record last updated
- 2026-09-16CISA federal remediation deadline (BOD 22-01)
CISA Known Exploited Vulnerability
BerriAI LiteLLM Improper Authentication Vulnerability
Affected product
BerriAI LiteLLM
Remediation Steps
- Apply the vendor security update for BerriAI LiteLLM as a priority.
- Restrict network exposure of the affected service to trusted sources until patched.
- Review logs and detections for indicators of exploitation.
- Confirm fixed versions against the official vendor advisory before deploying.
References
- https://github.com/BerriAI/litellm/commit/73869f0faf7d11ee21adcb5f91b8c33a340b6c2c
- https://github.com/BerriAI/litellm/pull/26463
- https://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q
- https://nvd.nist.gov/vuln/detail/CVE-2026-59822
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Referenced in our briefings & reports
- Vulnerability Priority Report – Week 3 of September 2026 (September 21 – 27)
- Vulnerability Priority Report – Week 2 of September 2026 (September 14 – 20)
- Vulnerability Priority Report – Week 1 of September 2026 (September 7 – 13)
- Vulnerability Priority Report – Week 5 of August 2026 (August 31 – September 6)
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🤖 This CVE page is generated by defend.network from NVD, CISA KEV, EPSS, and our verified daily briefings. Severity and exploitation data come from official sources; always verify remediation steps against the official vendor advisory before acting in production.