Vulnerability Description
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 Score
CRITICAL
Related Weaknesses (CWE)
References
- https://github.com/lm-sys/FastChat
- https://github.com/lm-sys/FastChat/blob/v0.2.36/fastchat/serve/controller.py
- https://github.com/lm-sys/FastChat/issues/3886
- https://www.vulncheck.com/advisories/fastchat-unauthenticated-worker-registratio
FAQ
What is CVE-2026-85695?
CVE-2026-85695 is a vulnerability with a CVSS score of 9.4 (CRITICAL). 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 f...
How severe is CVE-2026-85695?
CVE-2026-85695 has been rated CRITICAL with a CVSS base score of 9.4/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-85695?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.