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Vulnerability · Published Apr 20, 2026 · Assigned by VulDB

CVE-2026-6607lm-sys fastchat Worker API Endpoint api_generate resource consumption

Medium 5.3

In plain English

A medium-severity uncontrolled resource consumption in fastchat from lm-sys. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.6%top 49.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

A security vulnerability has been detected in lm-sys fastchat up to 0.2.36. This issue affects the function api_generate of the component Worker API Endpoint. The manipulation leads to resource consumption. The attack can be initiated remotely. The exploit has been disclosed publicly and may be used. The identifier of the patch is c9e84b89c91d45191dc24466888de526fa04cf33. It is suggested to install a patch to address this issue. Commit ff66426 patched this issue in api_generate of base_model_worker.py and did miss other entry points.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
PyPIfschatno fix listedGHSA-5h65-jx66-j7p5
PyPIfschatno fix listedPYSEC-2026-2484

Affected products (as reported)

VendorProductVersions
lm-sys fastchat 0.2.00.2.10.2.20.2.30.2.40.2.50.2.60.2.7

Weakness: CWE-400, CWE-404 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C

References