LiteLLM Proxy Bypass Allows Server-Side Request Redirection

# LiteLLM Proxy Bypass Allows Server-Side Request Redirection

https://gcdradar.vercel.app/incidents/litellm-proxy-bypass-allows-server-side-request-redirection · AIR-2026-0135 · closed 2026-09-16

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Fix status unknown
- First reported: 2026-09-16
- AI role: Attack on AI
- Products: LiteLLM
- CVE ids: CVE-2026-59823
- CVSS: 5.3

## Summary

Prior to 1.83.9, LiteLLM allowed authenticated callers to place api_base inside user_config to bypass safety checks. This lets attackers redirect outbound router requests to internal or external hosts.

## What to do

No action recorded; read the sources below and the vendor's advisory.

## Latest updates

- 2026-09-17: CVE-2026-59823: LiteLLM Proxy has server-side request forgery via the `user_config` request parameter (https://github.com/advisories/GHSA-hx8v-g79f-8w5f)
- 2026-09-16: CVE-2026-59823: LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. (https://nvd.nist.gov/vuln/detail/CVE-2026-59823)

## Sources

- 2026-09-16 NVD: CVE-2026-59823: LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. https://nvd.nist.gov/vuln/detail/CVE-2026-59823
- 2026-09-17 GitHub Advisory Database: CVE-2026-59823: LiteLLM Proxy has server-side request forgery via the `user_config` request parameter https://github.com/advisories/GHSA-hx8v-g79f-8w5f

Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.