CVE-2026-59822Network attack vector

Unauthenticated MCP tool access via OAuth2 fallback

Published Jul 8, 2026 · Updated Jul 8, 2026

Authentication bypass in BerriAI LiteLLM before 1.84.0 allows remote attackers to access configured MCP tools with a fabricated bearer token. MCPRequestHandler.process_mcp_request treats failed LiteLLM key validation as OAuth2 passthrough and substitutes an empty UserAPIKeyAuth object. A network-reachable Streamable HTTP MCP route and a configured MCP server are required; successful requests can list or call tools and access connected services.

CVSS severity8.8
High
EPSS probability0.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in BerriAI LiteLLM before 1.84.0 allows remote attackers to access configured MCP tools with a fabricated bearer token. MCPRequestHandler.process_mcp_request treats failed LiteLLM key validation as OAuth2 passthrough and substitutes an empty UserAPIKeyAuth object. A network-reachable Streamable HTTP MCP route and a configured MCP server are required; successful requests can list or call tools and access connected services.

The record

CVE
CVE-2026-59822
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
Berri AI
Product
LiteLLM
Classifications
CWE-287, CWE-306, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.84.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Berri AI · LiteLLMversion=< 1.84.0

Published CVSS scores

8.2NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
8.8GitHub, Inc.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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
CWE-306Missing Authentication for Critical Function
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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