Resource exhaustion in Lm-sys Fastchat
CVE-2026-6607
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 remo…
Vulnerability class: DoS (Denial of Service)
EPSS: 0.000 (7.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). 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.
Affected products
- Lm-sys Fastchat — versions 0.2.0, 0.2.1, 0.2.2
Weakness classification (CWE)
References
- VDB-358242 | lm-sys fastchat Worker API Endpoint api_generate resource consumption (vdb-entry, technical-description)
- VDB-358242 | CTI Indicators (IOB, IOC, TTP, IOA) (signature, permissions-required)
- Submit #792227 | LM-Sys FastChat <= 0.2.36 Denial of Service (CWE-400) (third-party-advisory)
- github.com/lm-sys/FastChat/issues/3833 (issue-tracking)
- github.com/lm-sys/FastChat/pull/3835 (issue-tracking, patch)
- gist.github.com/YLChen-007/87216a2d97a882d619e11dc67cd473b5 (exploit)
- github.com/lm-sys/FastChat/commit/c9e84b89c91d45191dc24466888de526fa04cf33 (patch)
- github.com/lm-sys/FastChat/ (product)
Frequently asked questions
- What is CVE-2026-6607?
- CVE-2026-6607 is a medium-severity vulnerability in Lm-sys Fastchat, classified under Uncontrolled Resource Consumption. CVSS score: 5.3/10. Published 2026-04-20.
- How severe is CVE-2026-6607?
- Medium severity. CVSS v3 base score is 5.3 out of 10.