Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
High, CVSS 8.8Exploited · CISA KEVamended

LiteLLM: MCP Authentication Bypass via OAuth2 Passthrough Fallback

CVE-2026-59822GHSA-7488-6r32-c95q

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (litellm 1.84.0), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

Add to your agent

Affected packages

  • PyPI litellm

    Affected
    < 1.84.0
    Fixed in
    1.84.0

Sources

Severity and exploitation
Exploitation
Confirmed: listed in the CISA Known Exploited Vulnerabilities catalog.
CVSS 4.0
8.8 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N · score source
EPSS
  • CVE-2026-59822: 0.84% estimated exploitation activity in the next 30 days; percentile 57.76 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Impact LiteLLM's MCP Streamable HTTP endpoint could allow an unauthenticated attacker to establish an authenticated MCP session using an arbitrary Bearer token. The MCP auth handler supported OAuth2 passthrough for upstream MCP servers, but the fallback path could replace failed LiteLLM key validation with an empty UserAPIKeyAuth() object. This allowed requests with a fabricated Authorization header to reach MCP tooling without a valid LiteLLM key. An attacker could use this to list and call configured MCP tools and access connected services exposed through MCP. Patches The issue is fixed in 1.84.0. We recommend upgrading to 1.84.0 or later. Workarounds If upgrading is not immediately possible, disable MCP routes or block access to /mcp/ and related MCP endpoints at your reverse proxy or API gateway. References v1.84.0

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 4 · amended ·

    Amended from ghsa record GHSA-7488-6r32-c95q

  2. Revision 3 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 2 · evidence added ·

    CISA KEV confirmed exploitation for CVE-2026-59822 (date added 2026-09-02). Customer workflow unchanged.

  4. Revision 1 · created ·

    Published from osv record GHSA-7488-6r32-c95q

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-59822

Advisory: LiteLLM: MCP Authentication Bypass via OAuth2 Passthrough Fallback
IDs: CVE-2026-59822, GHSA-7488-6r32-c95q
Record: https://patchnext.com/advisories/cve-2026-59822 (revision 4, source checked 26 Oct 2026, 13:49 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: confirmed: listed in the CISA Known Exploited Vulnerabilities catalog.
Vendor response: Vendor fix available; fixed versions by package: litellm 1.84.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI litellm: affected < 1.84.0; fixed in 1.84.0

## Suggested inspection (read-only)
- `python -m pip show litellm`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on litellm.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-7488-6r32-c95q (OSV record GHSA-7488-6r32-c95q lists affected ranges: PyPI litellm >=0 <1.84.0 (fixed))
- Verified: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json (CISA added CVE-2026-59822 to the Known Exploited Vulnerabilities catalog on 2026-09-02.)
- Verified: https://www.cisa.gov/known-exploited-vulnerabilities-catalog (CISA added CVE-2026-59822 to the Known Exploited Vulnerabilities catalog on 2026-09-02.)
- Verified: https://github.com/advisories/GHSA-7488-6r32-c95q (GitHub-reviewed advisory GHSA-7488-6r32-c95q lists affected ranges: PyPI litellm >=0 <1.84.0)

Commands are suggestions: review each one before running it.

Loading voting…