Server Side Request Forgery in lm-sys/fastchat

published 2025-03-20 19 mo ago modified 2026-07-07 4 mo ago also GHSA-g44m-hpf4-vmrp , PYSEC-2026-1396 , EUVD-2025-7008

cvss: 7.5; version 3.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.8%; EPSS 0.8% chance of exploitation in 30 days, percentile 55%
public exploits: 0; none known

A Server-Side Request Forgery (SSRF) vulnerability was identified in the lm-sys/fastchat web server, specifically in the affected version git 2c68a13. This vulnerability allows an attacker to access internal server resources and data that are otherwise inaccessible, such as AWS metadata credentials.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: partial
Assessed: 19 mo ago (2025-03-20)

Exploit prediction

0.76% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

huntr.com https://huntr.com/bounties/c9cc3f28-ee9f-4d2d-9ee5-8c6455a11892 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.0	7.5	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
OSV	3.0	7.5	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
GitHub	3.0	7.5	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
pypi	fschat	<=0.2.36	no fix listed

Affected products

lm-sys lm-sys/fastchat

Classification

Weakness

CWE-918 Server-Side Request Forgery

References

huntr.com /bounties/c9cc3f28-ee9f-4d2d-9ee5-8c6455a11892
web, exploit, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2024-12376
advisory
github.com /lm-sys/FastChat
package
pypi.org /project/fschat
package
github.com /advisories/GHSA-g44m-hpf4-vmrp
advisory

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary