LiteLLMGHSA-4jcj-7x88-m979
LiteLLM: MCP Proxy Has Improper Authentication
Medium7.3CVE-2026-12773 · Published Jun 21, 2026 · updated Sep 10, 2026
A weakness has been identified in BerriAI litellm up to 1.59.8. Affected is the function UserAPIKeyAuth of the file litellm/proxy/_experimental/mcp_server/auth/user_api_key_auth_mcp.py of the component MCP Proxy. Executing a manipulation can lead to improper authentication. The attack may be launched remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure.
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| litellm PyPI | < 1.84.0 | 1.84.0 |
Details and references
- CVSS 3.1
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
- Severity from
- GitHub (reviewed advisory)
- Weakness
- CWE-287, CWE-303
- Also known as
- CVE-2026-12773
- nvd.nist.gov/vuln/detail/CVE-2026-12773
- github.com/BerriAI/litellm/commit/73869f0faf7d11ee21adcb5f91b8c33a340b6c2c
- access.redhat.com/security/cve/CVE-2026-12773
- bugzilla.redhat.com/show_bug.cgi?id=2491112
- gist.github.com/YLChen-007/3cfaad10a69d7a15e4d4d458cb53309e
- github.com/BerriAI/litellm
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12773.json
- vuldb.com/cve/CVE-2026-12773
- vuldb.com/submit/811282
- vuldb.com/vuln/372515
- vuldb.com/vuln/372515/cti
More LiteLLM advisories
All LiteLLM| Date | Advisory | Severity | Fixed in |
|---|---|---|---|
| Jun 21 | BerriAI litellm has SSRF via Unvalidated spec_path URL in MCP OpenAPI Spec Loader Low6.3Jun 21 | Low6.3 | No fix yet |
| Jun 21 | BerriAI litellm: UI User Enumeration leads to System-Wide Information DisclosureLow4.3Jun 21 | Low4.3 | No fix yet |
| Jun 21 | LiteLLM: improper authorizationLow6.3Jun 21 | Low6.3 | No fix yet |
| Jun 21 | BerriAI litellm: SSO Login Does Not Invalidate Previous UI Session TokensLow6.3Jun 21 | Low6.3 | No fix yet |
| Jun 21 | LiteLLM: SSO Debug Flow Has Improper AuthenticationMedium7.3Jun 21 | Medium7.3 | No fix yet |
| Jun 21 | LiteLLM: Admin Key Handler Has Improper AuthorizationLow5.4Jun 21 | Low5.4 | No fix yet |