CVEvulnerability
CVE-2026-85695
9.3 CRITICAL
Official page ↗
- Status
- Deferred
- Published
- 2026-09-04
- Last modified
- 2026-09-10
- Assigner
- [email protected]
- CVSS 4.0 ([email protected])
- 9.3 CRITICAL — CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CVSS 3.1 ([email protected])
- 9.4 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
- Weaknesses
- CWE-306
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.
Related
Weakness · CWE (1)
- CWE-306 Missing Authentication for Critical Functionality weakness
References
- https://github.com/lm-sys/FastChat github.com
- https://github.com/lm-sys/FastChat/blob/v0.2.36/fastchat/serve/controller.py github.com
- https://github.com/lm-sys/FastChat/issues/3886 github.com
- https://www.vulncheck.com/advisories/fastchat-unauthenticated-worker-registration-ssrf-and-model-spoofing www.vulncheck.com