CVE-2026-6608 MEDIUM

CVE-2026-6608: lm-sys fastchat Arena Side-by-Side View add_text control flow

Vendor Lm-Sys
Product fastchat
Weakness CWE-670
Published April 20, 2026
Last update April 20, 2026

CVSS base score

6.9/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 20, 2026 CVE published
April 20, 2026 Record updated