CVE-2026-59822

highpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.008 · 57 %ileexploit · PoCDEEUUS
grimoire priorityP0 · Act now
Exploitable?
Yes · in the wild
CISA KEV · 1 exploit · PoC
Likely / severe?
0.84% (57th) EPSS
CVSS 8.2 · high
Is it mine?
7 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · osv · cert_bund

added 2026-09-02remediate by 2026-09-16

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.

EPSS · scored 2026-10-23

BerriAI LiteLLM Improper Authentication Vulnerability

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

8.8
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.18.2highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 4.2
v4.08.8highCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:Nsecondary · ENISA EU
v4.08.8highCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · security-advisories@github.com
v4.08.8highCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:A/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: active · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-287USCWE-287USCWE-306US
04

exploits (1)

Public proof-of-concept and weaponised exploit code.

05

affected products (7)

Products and version ranges known to be affected.

06

advisories (3)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-2263LiteLLM: Mehrere SchwachstellenDeutsch2026-07-08csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in LiteLLM ausnutzen, um Informationen offenzulegen, Daten zu manipulieren, Code auszuführen und um Sicherheitsmaßnahmen zu umgehen.

  • GHSA-7488-6r32-c95qLiteLLM: MCP Authentication Bypass via OAuth2 Passthrough Fallback2026-07-22ghsa · osvUS

    ### 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](https://github.com/BerriAI/litellm/releases/tag/v1.84.0)

  • PYSEC-2026-3479LiteLLM: MCP Authentication Bypass via OAuth2 Passthrough Fallback2026-07-23vendor · osvUS

    ### 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](https://github.com/BerriAI/litellm/releases/tag/v1.84.0)

07

also known as (6)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdosvcert_bundnvdNVDCVE.orgMITRE
published 2026-07-08modified 2026-09-03
09

references (15)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan