Home/CVE/A vulnerability was detected in lm-sys fastchat up to 0.2.36. Impacted is the function add_text of the component Arena S
CVE

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 S

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.

MEDIUM · CVSS 5.3 EPSS 0.00049
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-670Always-Incorrect Control Flow Implementation
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
PyPI fschat MODERATE
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Scoring & Timeline

5.3
MEDIUM · CVSS v3.1 · cna@vuldb.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD20 Apr 2026 · 06:16 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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References & Sources

6
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://gist.github.com/YLChen-007/e45039d23e698222d887ee09735d9d36
https://github.com/lm-sys/FastChat/
https://github.com/lm-sys/FastChat/issues/3834
https://vuldb.com/submit/792228
https://vuldb.com/vuln/358243
https://vuldb.com/vuln/358243/cti
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