CVE-2026-59823

published 2026-09-16

CVE-2026-59823: LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.83.9, an authenticated LiteLLM Proxy caller with a valid…

Priority P3 34 medium 5.3 CVSS 4.0

AV N AC L AT N PR L UI N VC L VI N VA N SC L 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 X

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.83.9, an authenticated LiteLLM Proxy caller with a valid virtual key can place api_base inside the user_config request body to bypass is_request_body_safe, which blocks top-level api_base and base_url but previously did not inspect or reject user_config. Because user_config constructs the outbound router, the nested destination redirects a server-side request to an internal or external host selected by the caller and can expose endpoints the caller cannot otherwise access. This issue is fixed in version 1.83.9.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
berriai	litellm	< 1.83.9	1.83.9
litellm	litellm	>= 0 < 1.83.9	1.83.9

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CWE-918