CVE-2026-85695
criticalFastChat contains an authentication bypass vulnerability in the /register_worker endpoint that allows unauthenticated attackers to register arbitrary worker ad…
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/lm-sys/FastChat disclosure@vulncheck.com
- https://github.com/lm-sys/FastChat/blob/v0.2.36/fastchat/serve/controller.py disclosure@vulncheck.com
- https://github.com/lm-sys/FastChat/issues/3886 disclosure@vulncheck.com
- https://www.vulncheck.com/advisories/fastchat-unauthenticated-worker-registration-ssrf-and... disclosure@vulncheck.com