CVE-2026-59823 Security Details

CVE ID

CVE-2026-59823

CWE

CWE-918

CVE Description

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.

Published

Sep 18, 2026

CVSS Score & Severity

5.3Medium

CVSS Vector

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

EPSS Score

0.439%

Malware

malware

KEV Status

Not in KEV Catalog: No known exploits

Affected Ecosystems

affected

Source

National Vulnerability Database

References

GitHub · PR #25827PROJECT

GitHub · BerriAI/litellmPROJECT