lm-sys fastchat up to 0.2.36 Worker API Endpoint api_generate resource consumption

Summaryinfo

A vulnerability labeled as problematic has been found in lm-sys fastchat up to 0.2.36. Impacted is the function api_generate of the component Worker API Endpoint. The manipulation results in resource consumption. This vulnerability is reported as CVE-2026-6607. The attack can be launched remotely. Moreover, an exploit is present. A patch should be applied to remediate this issue. Commit ff66426 patched this issue in api_generate of base_model_worker.py and did miss other entry points.

Detailsinfo

A vulnerability was found in lm-sys fastchat up to 0.2.36. It has been classified as problematic. Affected is the function api_generate of the component Worker API Endpoint. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-6607. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details and a public exploit are known. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

The exploit is shared for download at gist.github.com. It is declared as proof-of-concept. Commit ff66426 patched this issue in api_generate of base_model_worker.py and did miss other entry points.

Applying the patch c9e84b89c91d45191dc24466888de526fa04cf33 is able to eliminate this problem. The bugfix is ready for download at github.com.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Chat Software

Vendor

• lm-sys

Name

• fastchat

Version

• 0.2.0
• 0.2.1
• 0.2.2
• 0.2.3
• 0.2.4
• 0.2.5
• 0.2.6
• 0.2.7
• 0.2.8
• 0.2.9
• 0.2.10
• 0.2.11
• 0.2.12
• 0.2.13
• 0.2.14
• 0.2.15
• 0.2.16
• 0.2.17
• 0.2.18
• 0.2.19
• 0.2.20
• 0.2.21
• 0.2.22
• 0.2.23
• 0.2.24
• 0.2.25
• 0.2.26
• 0.2.27
• 0.2.28
• 0.2.29
• 0.2.30
• 0.2.31
• 0.2.32
• 0.2.33
• 0.2.34
• 0.2.35
• 0.2.36

License

• open-source

Website

• Product: https://github.com/lm-sys/FastChat/

CPE 2.3info

• 🔒
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CPE 2.2info

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Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Submitinfo

Accepted

• Submit #792227: LM-Sys FastChat <= 0.2.36 Denial of Service (CWE-400) (by Eric-f)

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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