lm-sys fastchat up to 0.2.36 Arena Side-by-Side View add_text control flow

Summaryinfo

A vulnerability marked as problematic has been reported in lm-sys fastchat up to 0.2.36. The affected element is the function add_text of the component Arena Side-by-Side View Handler. This manipulation causes control flow. This vulnerability appears as CVE-2026-6608. The attack may be initiated remotely. In addition, an exploit is available. The root cause was fixed in commit 34eca62 for gradio_block_arena_named.py, but three other files were missed.

Detailsinfo

A vulnerability was found in lm-sys fastchat up to 0.2.36. It has been declared as problematic. Affected by this vulnerability is the function add_text of the component Arena Side-by-Side View Handler. The manipulation with an unknown input leads to a control flow vulnerability. The CWE definition for the vulnerability is CWE-670. The code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated. As an impact it is known to affect integrity.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-6608. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details and also a public exploit are known.

It is possible to download the exploit at gist.github.com. It is declared as proof-of-concept. The root cause was fixed in commit 34eca62 for gradio_block_arena_named.py, but three other files were missed.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-23780). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 4.8

VulDB Base Score: 5.3
VulDB Temp Score: 4.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Control flow
CWE: CWE-670
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/19/2026 Advisory disclosed
04/19/2026 +0 days VulDB entry created
04/20/2026 +1 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: 3834
Status: Not defined

CVE: CVE-2026-6608 (🔒)
GCVE (CVE): GCVE-0-2026-6608
GCVE (VulDB): GCVE-100-358243
EUVD: 🔒
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 04/19/2026 18:04
Updated: 04/20/2026 10:56
Changes: 04/19/2026 18:04 (58), 04/20/2026 10:56 (1)
Complete: 🔍
Submitter: Eric-f
Cache ID: 216::103

Submitinfo

Accepted

  • Submit #792228: LM-Sys FastChat <= 0.2.36 Content Moderation Bypass (CWE-670) (by Eric-f)

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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