{"id":"CVE-2026-59823","aliases":["GHSA-hx8v-g79f-8w5f","PYSEC-2026-4070"],"url":"https://o3.security/vulnerability/CVE-2026-59823","summary":"LiteLLM: Server-side request forgery via the `user_config` request parameter in LiteLLM Proxy","details":"### Summary\nA server-side request forgery in LiteLLM Proxy lets an authenticated caller redirect the\nproxy's outbound request to a host of their choosing by smuggling an `api_base` inside the\n`user_config` request body, bypassing the existing parameter guard.\n\n### Details\nLiteLLM Proxy validates request bodies with `is_request_body_safe`, which blocks the\n`api_base` and `base_url` parameters but does not cover `user_config`. The `user_config`\nobject is used to build the outbound router for a request, so a caller can place an\n`api_base` inside it and reach an arbitrary host. The guard only inspected the two\ntop-level keys, so the same `api_base` nested inside `user_config` was never checked.\n\nExploitation requires a valid virtual key.\n\n### Impact\nAn authenticated caller can make the proxy issue server-side requests to internal or\nexternal hosts of their choosing, reaching endpoints the caller cannot otherwise access.\n\n### Affected / Patched\nAffected: `<= 1.83.8`\nPatched: `1.83.9`\n\n### Remediation\nUpgrade to 1.83.9 or later (released 2026-04-17).","published":"2026-09-16T18:36:21.105Z","modified":"2026-10-28T02:30:26.669512966Z","cvss":null,"epss":{"score":0.00439,"percentile":0.37429,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"litellm","fixedVersion":"1.83.9"}],"fix":{"url":"https://github.com/BerriAI/litellm/commit/47214be317f45a2d2ac08258362e0481411eb427","label":"BerriAI/litellm@47214be"},"references":[{"type":"ADVISORY","url":"https://github.com/BerriAI/litellm/security/advisories/GHSA-hx8v-g79f-8w5f"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59823.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59823"},{"type":"FIX","url":"https://github.com/BerriAI/litellm/commit/47214be317f45a2d2ac08258362e0481411eb427"},{"type":"FIX","url":"https://github.com/BerriAI/litellm/pull/25827"},{"type":"PACKAGE","url":"https://github.com/BerriAI/litellm"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:30:26.669512966Z"}}