{"id":"CVE-2026-59823","title":"LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format","summary":"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_req…","severity":"medium","cvss":5.3,"cvssVector":"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","cwe":["CWE-918"],"vendor":"BerriAI","product":"litellm","affected":["litellm < 1.83.9"],"patched":["litellm 1.83.9"],"published":"2026-09-16","updated":"2026-09-17","sourceUpdated":"2026-09-17T16:17:32.037","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-59823","references":[{"url":"https://github.com/BerriAI/litellm/commit/47214be317f45a2d2ac08258362e0481411eb427","label":"security-advisories@github.com"},{"url":"https://github.com/BerriAI/litellm/pull/25827","label":"security-advisories@github.com"},{"url":"https://github.com/BerriAI/litellm/security/advisories/GHSA-hx8v-g79f-8w5f","label":"security-advisories@github.com"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59823"},{"url":"https://github.com/advisories/GHSA-hx8v-g79f-8w5f"},{"url":"https://github.com/BerriAI/litellm"}],"tags":["nvd","cve.org","ghsa","pip","osv"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-17T15:07:39.533665Z"},"cvssSource":"cna","aliases":["GHSA-hx8v-g79f-8w5f"],"ecosystem":"pip","ingestedAt":"2026-09-16T19:02:30.730Z","epss":0.00439,"epssPercentile":0.37603,"slug":"CVE-2026-59823","body":"## Overview\n\nLiteLLM 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-59823)\n\nAffected packages:\n\n- `litellm <= 1.83.8`\n\nPatched in:\n\n- `litellm 1.83.9`\n\nSource: https://github.com/advisories/GHSA-hx8v-g79f-8w5f","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}