CVE-2026-6608

MEDIUM

lm-sys fastchat Arena Side-by-Side View add_text control flow

Title source: cna
STIX 2.1

Description

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.

References (6)

Core 6
Core References
Vdb Entry, Technical Description vdb-entry technical-description
VDB-358243 | lm-sys fastchat Arena Side-by-Side View add_text control flow
https://vuldb.com/vuln/358243
Signature, Permissions Required signature permissions-required
VDB-358243 | CTI Indicators (IOB, IOC, IOA)
https://vuldb.com/vuln/358243/cti
Third Party Advisory third-party-advisory
Submit #792228 | LM-Sys FastChat <= 0.2.36 Content Moderation Bypass (CWE-670)
https://vuldb.com/submit/792228
Issue Tracking issue-tracking
https://github.com/lm-sys/FastChat/issues/3834

Scores

CVSS v3 5.3
EPSS 0.0031
EPSS Percentile 22.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-670
Status published
Products (38)
lm-sys/fastchat 0.2.0
lm-sys/fastchat 0.2.1
lm-sys/fastchat 0.2.10
lm-sys/fastchat 0.2.11
lm-sys/fastchat 0.2.12
lm-sys/fastchat 0.2.13
lm-sys/fastchat 0.2.14
lm-sys/fastchat 0.2.15
lm-sys/fastchat 0.2.16
lm-sys/fastchat 0.2.17
... and 28 more
Published Apr 20, 2026
Tracked Since Apr 20, 2026