Auth bypass in Berriai Litellm
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.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.008 (56.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 56.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.008 · change: -0.000
Affected products
- Berriai Litellm — versions < 1.84.0
- Litellm
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
Required action: 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.
Public proof-of-concept exploits
References
- github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q (Patch, Mitigation, Vendor Advisory)
- github.com/BerriAI/litellm/pull/26463 (Patch, Issue Tracking)
- github.com/BerriAI/litellm/commit/73869f0faf7d11ee21adcb5f91b8c33a340b6c2c (Patch)
- github.com/BerriAI/litellm/releases/tag/v1.84.0 (Product, Release Notes)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Third Party Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2026-59822?
- CVE-2026-59822 is a high-severity vulnerability in Berriai Litellm, classified under Improper Authentication. CVSS score: 8.2/10. Published 2026-07-08.
- How severe is CVE-2026-59822?
- High severity. CVSS v3 base score is 8.2 out of 10.
- Is CVE-2026-59822 known to be exploited?
- Yes. CVE-2026-59822 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-09-02), indicating it is being actively exploited. 1 public proof-of-concept repositories are indexed.