{"cve_id":"CVE-2026-59822","published":"2026-07-08T20:16:57.683000+00:00","last_modified":"2026-10-25T17:10:00.197000+00:00","vuln_status":"Analyzed","description":"LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.84.0, LiteLLM's MCP Streamable HTTP endpoint allowed an unauthenticated attacker to use a fabricated Authorization header to trigger an OAuth2 passthrough fallback path that replaced failed LiteLLM key validation with an empty UserAPIKeyAuth() object, allowing requests to reach MCP tooling without a valid LiteLLM key. This issue is fixed in version 1.84.0.","cvss_version":"3.1","cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","base_score":8.2,"base_severity":"HIGH","attack_vector":"NETWORK","privileges_req":"NONE","user_interaction":"NONE","scope":"UNCHANGED","impact_c":"HIGH","impact_i":"LOW","impact_a":"NONE","cwe_ids":["CWE-287","CWE-306"],"in_kev":true,"kev_date_added":"2026-09-02","kev_ransomware":false,"epss_score":0.00836,"epss_percentile":0.57733,"cap_rule_version":"0.1.1","stage":"INITIAL_ACCESS","req_access":"NONE","req_vector":"NETWORK","req_user_interaction":false,"grant_access":"USER","caps":["AUTH_BYPASS","INFO_DISCLOSURE","TAMPER"],"terminal":false,"cap_confidence":"high","ingested_at":"2026-10-28T03:40:00.565350+00:00","first_seen":"2026-07-08T20:16:57.683000+00:00","kev_first_seen":"2026-09-02T00:00:00+00:00","novelty_score":0.0,"novelty_reasons":[],"novelty_at":null,"vendors":["litellm"],"products":["litellm"],"affected":[{"vendor":"litellm","product":"litellm","ranges":["< 1.84.0"]}]}