CVE-2026-6607lm-sys fastchat Worker API Endpoint api_generate resource consumption
- 6.9MediumCVSS base score
- 0.62%Exploitation in 30 daysEPSS · top 50% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
Timeline
ID reserved
By VulDB
- 1 day later
· 1 day later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulDBCNA (assigner) | 4.0 | Medium6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P |
| VulDBCNA (assigner) | 3.1 | Medium5.3 | 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 |
| VulDBCNA (assigner) | 3.0 | Medium5.3 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C |
| VulDBCNA (assigner) | 2.0 | Medium5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P/E:POC/RL:OF/RC:C |
| NVDNVD · Deferred | 4.0 | Medium5.5 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.62% · top 50% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.9.
Affected products
- affected 0.2.0
- affected 0.2.1
- affected 0.2.2
- affected 0.2.3
- affected 0.2.4
- affected 0.2.5
- affected 0.2.6
- affected 0.2.7
- affected 0.2.8
- affected 0.2.9
- affected 0.2.10
- affected 0.2.11
- affected 0.2.12
- affected 0.2.13
- affected 0.2.14
- affected 0.2.15
- affected 0.2.16
- affected 0.2.17
- affected 0.2.18
- affected 0.2.19
- affected 0.2.20
- affected 0.2.21
- affected 0.2.22
- affected 0.2.23
- affected 0.2.24
- affected 0.2.25
- affected 0.2.26
- affected 0.2.27
- affected 0.2.28
- affected 0.2.29
- affected 0.2.30
- affected 0.2.31
- affected 0.2.32
- affected 0.2.33
- affected 0.2.34
- affected 0.2.35
- affected 0.2.36
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIfschatGHSA-5h65-jx66-j7p5 (opens in a new tab)
References
References8
- VDB-358242 | lm-sys fastchat Worker API Endpoint api_generate resource consumption (opens in a new tab)vdb-entrytechnical-description
- VDB-358242 | CTI Indicators (IOB, IOC, TTP, IOA) (opens in a new tab)signaturepermissions-required
- Submit #792227 | LM-Sys FastChat <= 0.2.36 Denial of Service (CWE-400) (opens in a new tab)third-party-advisory
- https://github.com/lm-sys/FastChat/issues/3833 (opens in a new tab)issue-tracking
- https://github.com/lm-sys/FastChat/pull/3835 (opens in a new tab)issue-trackingpatch
- https://gist.github.com/YLChen-007/87216a2d97a882d619e11dc67cd473b5 (opens in a new tab)exploit
- https://github.com/lm-sys/FastChat/commit/c9e84b89c91d45191dc24466888de526fa04cf33 (opens in a new tab)patch
- https://github.com/lm-sys/FastChat/ (opens in a new tab)product
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-23778 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-5h65-jx66-j7p5 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-6607)Record last updated .