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Fencer Vulns
low 2.6

CVE-2026-7846 json

chatchat-space Langchain-Chatchat OpenAI-Compatible File Upload API openai_routes.py files toctou

published 2026-05-05 6 mo ago modified 2026-07-24 3 mo ago also GHSA-x229-w2j4-h748 , PYSEC-2026-2559 , EUVD-2026-27392

cvss
2.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

A vulnerability has been found in chatchat-space Langchain-Chatchat up to 0.3.1.3. Impacted is the function files of the file libs/chatchat-server/chatchat/server/api_server/openai_routes.py of the component OpenAI-Compatible File Upload API. Such manipulation of the argument file.filename leads to time-of-check time-of-use. Access to the local network is required for this attack to succeed. The attack requires a high level of complexity. The exploitability is considered difficult. The exploit has been disclosed to the public and may be used. The project was informed of the problem early through an issue report but has not responded yet.

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/3em0/cve_repo/blob/main/Langchain-Chatchat/Vuln-2-Silent-File-Overwrite.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 2.1 CVSS:4.0/AV:A/AC:H/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
CNA 3.1 2.6 CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA 3.0 2.6 CVSS:3.0/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA 2.0 1.4 AV:A/AC:H/Au:S/C:N/I:P/A:N/E:POC/RL:ND/RC:UR
CNA 4.0 1.2 CVSS:4.0/AV:A/AC:H/AT:N/PR:L/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 2.6 CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
CNA 2.0 1.4 AV:A/AC:H/Au:S/C:N/I:P/A:N
GitHub 3.1 2.6 CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
OSV 3.1 2.6 CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
pypi langchain-chatchat
<=0.3.1.3
 no fix listed

Affected products

  • chatchat-space Langchain-Chatchat

Classification

Weakness
  • CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

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.