CVE-2026-6608 json
lm-sys fastchat Arena Side-by-Side View add_text control flow
published 2026-04-20 6 mo ago modified 2026-10-26 13 d ago also GHSA-f3q6-69f3-vwch , PYSEC-2026-2485 , EUVD-2026-23780
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 23%
- public exploits
- 0
- none known
Summary
A vulnerability was detected in lm-sys fastchat up to 0.2.36. Impacted is the function add_text of the component Arena Side-by-Side View Handler. The manipulation results in incorrect control flow. The attack can be launched remotely. The exploit is now public and may be used. The root cause was fixed in commit 34eca62 for gradio_block_arena_named.py, but three other files were missed.
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- gist.github.com https://gist.github.com/YLChen-007/e45039d23e698222d887ee09735d9d36 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:L/VA:N/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:L/A:N/E:P/RL:X/RC:R |
| CNA | 3.0 | 5.3 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R |
| CNA | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:P/A:N/E:POC/RL:ND/RC:UR |
| CNA | 4.0 | 5.5 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/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:L/A:N |
| CNA | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:P/A:N |
| OSV | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| GitHub | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | fschat | <=0.2.36 |
no fix listed |
Affected products
- lm-sys fastchat
Classification
- Weakness
-
- CWE-670 Always-Incorrect Control Flow Implementation
References
-
gist.github.com
/YLChen-007/e45039d23e698222d887ee09735d9d36
exploit, web
-
vuldb.com
/vuln/358243
vdb-entry, technical-description, web
-
vuldb.com
/vuln/358243/cti
signature, permissions-required, web
-
vuldb.com
/submit/792228
third-party-advisory, web
-
github.com
/lm-sys/FastChat/issues/3834
issue-tracking, web
-
github.com
/lm-sys/FastChat/
product
-
nvd.nist.gov
/vuln/detail/CVE-2026-6608
advisory
-
github.com
/lm-sys/FastChat
package
-
pypi.org
/project/fschat
package
-
github.com
/advisories/GHSA-f3q6-69f3-vwch
advisory
Sources
- CVE List CVE-2026-6608
- GitHub Advisory GHSA-f3q6-69f3-vwch
- NVD CVE-2026-6608
- OSV PYSEC-2026-2485
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