{"id":"CVE-2026-85695","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-85695","summary":"FastChat contains an authentication bypass vulnerability in the /register_worker endpoint that allows unauthenticated attackers to register arbitrary worker addresses and perform server-side…","details":"FastChat contains an authentication bypass vulnerability in the /register_worker endpoint that allows unauthenticated attackers to register arbitrary worker addresses and perform server-side request forgery. Attackers can register malicious workers under victim model names to intercept user prompts, images, and responses, or probe internal network ports across the worker mesh.","published":"2026-09-04T14:32:38.104Z","modified":"2026-09-04T15:05:18.305Z","cvss":{"score":9.4,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":null,"references":[{"type":"REPORT","url":"https://github.com/lm-sys/FastChat/issues/3886"},{"type":"WEB","url":"https://github.com/lm-sys/FastChat"},{"type":"WEB","url":"https://github.com/lm-sys/FastChat/blob/v0.2.36/fastchat/serve/controller.py"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/fastchat-unauthenticated-worker-registration-ssrf-and-model-spoofing"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-09-04T15:05:18.305Z"}}