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Fencer Intel
low 2.6

CVE-2026-7845 json

chatchat-space Langchain-Chatchat Vision Chat Paste Image dialogue.py PIL.Image.tobytes weak hash

published 6mo ago modified 3mo ago also GHSA-wmvv-fhm6-w34x , PYSEC-2026-2558 , EUVD-2026-27390

cvss
2.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

A flaw has been found in chatchat-space Langchain-Chatchat up to 0.3.1.3. This issue affects the function PIL.Image.tobytes of the file libs/chatchat-server/chatchat/webui_pages/dialogue/dialogue.py of the component Vision Chat Paste Image Handler. This manipulation of the argument paste_image.image_data causes use of weak hash. The attacker needs to be present on the local network. The attack is considered to have high complexity. The exploitability is assessed as difficult. The exploit has been published and may be used. The project was informed of the problem early through an issue report but has not responded yet.

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CISA SSVC

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

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/chatchat-space/Langchain-Chatchat/issues/5462 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/3em0/cve_repo/blob/main/Langchain-Chatchat/Vuln-1-tobytes-Hash-Collision.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
OSV 3.1 2.6 CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:L/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

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-328 Use of Weak Hash
  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm

References

Sources

Fencer Intel 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.