CVE-2026-6607 json
lm-sys fastchat Worker API Endpoint api_generate resource consumption
published 2026-04-20 6 mo ago modified 2026-10-26 13 d ago also GHSA-5h65-jx66-j7p5 , PYSEC-2026-2484 , EUVD-2026-23778
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 50%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- github.com/lm-sys/FastChat@c9e84b8 commit
- github.com/lm-sys/FastChat#3835 pull request
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.62% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- gist.github.com https://gist.github.com/YLChen-007/87216a2d97a882d619e11dc67cd473b5 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.9 | 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 |
| CNA | 3.1 | 5.3 | 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 |
| CNA | 3.0 | 5.3 | 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 |
| CNA | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P/E:POC/RL:OF/RC:C |
| CNA | 4.0 | 5.5 | 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 |
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| CNA | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P |
| OSV | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| GitHub | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | fschat | <=0.2.26 |
no fix listed |
Affected products
- lm-sys fastchat
Classification
References
-
github.com
/lm-sys/FastChat/pull/3835
issue-tracking, patch, web
-
github.com
/lm-sys/FastChat/commit/c9e84b89c91d45191dc24466888de526fa04cf33
patch, web
-
gist.github.com
/YLChen-007/87216a2d97a882d619e11dc67cd473b5
exploit, web
-
vuldb.com
/vuln/358242
vdb-entry, technical-description, web
-
vuldb.com
/vuln/358242/cti
signature, permissions-required, web
-
vuldb.com
/submit/792227
third-party-advisory, web
-
github.com
/lm-sys/FastChat/issues/3833
issue-tracking, web
-
github.com
/lm-sys/FastChat/
product
-
nvd.nist.gov
/vuln/detail/CVE-2026-6607
advisory
-
github.com
/lm-sys/FastChat
package
-
pypi.org
/project/fschat
package
-
github.com
/advisories/GHSA-5h65-jx66-j7p5
advisory
Sources
- CVE List CVE-2026-6607
- GitHub Advisory GHSA-5h65-jx66-j7p5
- NVD CVE-2026-6607
- OSV PYSEC-2026-2484
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