---
title: "CVE-2026-59822: BerriAI LiteLLM Improper Authentication Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-59822/
description: "CVE-2026-59822 (BerriAI LiteLLM): Exploited in the wild (CISA KEV). LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format.…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-07-08
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-59822"
kev: true
cvss: 8.8
epss: 0.00836
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-59822: BerriAI LiteLLM Improper Authentication Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run BerriAI LiteLLM. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-09-02, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-09-16 ; treat that as the outer limit, not the target.
- EPSS 0.8% , percentile 57: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 57% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Patch this week. LiteLLM Proxy: Three Exploited Flaws in CISA KEV — If you run a self-hosted LiteLLM Proxy older than 1.84.0, upgrade now and treat the provider keys it holds as possibly exposed; SDK-only users are not affected.

## What it is

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.

## Affected products (CVE record)

- BerriAI litellm: < 1.84.0

## Severity

- GitHub_M 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`

## Exploitation

- CISA KEV: added 2026-09-02; federal due date 2026-09-16. Known ransomware use: Unknown.
- CISA 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.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.84% probability of exploitation activity in the next 30 days; percentile 57.

## Sources

- [Listed in CISA KEV notes (github.com)](https://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q)
- [CVE.org record CVE-2026-59822](https://www.cve.org/CVERecord?id=CVE-2026-59822)
- [NVD entry CVE-2026-59822](https://nvd.nist.gov/vuln/detail/CVE-2026-59822)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-59822)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)
- [github.com](https://github.com/BerriAI/litellm/pull/26463)
- [github.com](https://github.com/BerriAI/litellm/commit/73869f0faf7d11ee21adcb5f91b8c33a340b6c2c)
- [github.com](https://github.com/BerriAI/litellm/releases/tag/v1.84.0)
- [wiz.io](https://www.wiz.io/blog/ai-infrastructure-honeypot)

---
Source page: https://erroneo.us/security/cve/CVE-2026-59822/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt