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CVE-2026-59822 BerriAI CVE debrief

CVE-2026-59822 is an authentication bypass vulnerability in LiteLLM's MCP Streamable HTTP endpoint. The issue allows an unauthenticated attacker to use a forged Authorization header to trigger an OAuth2 passthrough fallback path, potentially allowing unauthorized access to MCP tooling. This vulnerability affects LiteLLM versions prior to 1.84.0. Users should review their deployments and consider upgrading to the latest version.

Vendor
BerriAI
Product
litellm
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-08
Original CVE updated
2026-07-13
Advisory published
2026-07-08
Advisory updated
2026-07-13

Who should care

Users of LiteLLM, especially those using versions prior to 1.84.0, should be aware of this vulnerability and take steps to mitigate it. This includes reviewing their deployments, upgrading to the latest version, and implementing proper authentication and authorization mechanisms for the MCP Streamable HTTP endpoint.

Technical summary

The vulnerability exists in LiteLLM's MCP Streamable HTTP endpoint, where an unauthenticated attacker can use a fabricated Authorization header to trigger an OAuth2 passthrough fallback path. This replaces failed LiteLLM key validation with an empty UserAPIKeyAuth() object, allowing requests to reach MCP tooling without a valid LiteLLM key. The issue is fixed in version 1.84.0. Affected users should upgrade to this version or later.

Defensive priority

High

Recommended defensive actions

  • Upgrade to LiteLLM version 1.84.0 or later
  • Implement proper authentication and authorization mechanisms for the MCP Streamable HTTP endpoint
  • Monitor for suspicious activity on the MCP tooling
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-08T20:16:57.683Z and was last modified on 2026-07-13T13:32:04.470Z. The NVD entry is currently Analyzed. This information is based on the provided source corpus. Further verification is recommended to ensure accuracy.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-59822 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-59822

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-59822 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-59822

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.