CVE-2026-59823
LiteLLM: Server-side request forgery via the `user_config` request parameter in LiteLLM Proxy
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.
| CWE | CWE-918 |
| Vendor | berriai |
| Product | litellm |
| Published | Sep 16, 2026 |
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