Vulnerability in Lm-Sys Fastchat
CVE-2026-6608
A vulnerability was detected in lm-sys fastchat up to 0.2.36. Impacted is the function add_text of the component Arena Side-by-Side View Handler. The manipulation results in incorrect control flow. The attack can be launched remotely. The exploit is now public and may be used. The root cause was fixed in commit 34eca62 for gradio_block_arena_named.py, but three other files were missed.
EPSS: 0.003 (23.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
Affected products
- Lm-sys Fastchat — versions 0.2.0, 0.2.1, 0.2.2
Weakness classification (CWE)
References
- cna@vuldb.com (technical-description, vdb-entry)
- cna@vuldb.com (signature, permissions-required)
- cna@vuldb.com (third-party-advisory)
- cna@vuldb.com (issue-tracking)
- cna@vuldb.com (exploit)
- cna@vuldb.com (product)
Frequently asked questions
- What is CVE-2026-6608?
- CVE-2026-6608 is a medium-severity vulnerability in Lm-Sys Fastchat, classified under Always-Incorrect Control Flow Implementation. CVSS score: 5.3/10. Published 2026-04-20.
- How severe is CVE-2026-6608?
- Medium severity. CVSS v3 base score is 5.3 out of 10.