---
id: CVE-2026-7845
aliases:
  - GHSA-wmvv-fhm6-w34x
  - PYSEC-2026-2558
title: Langchain-Chatchat Uses a Broken or Risky Cryptographic Algorithm
summary: Langchain-Chatchat Uses a Broken or Risky Cryptographic Algorithm
severity: low
cvss: 2.6
cvssVector: 'CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N'
vendor: langchain-chatchat
product: langchain-chatchat
ecosystem: pip
affected:
  - langchain-chatchat <= 0.3.1.3
published: '2026-05-05'
updated: '2026-07-13'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-wmvv-fhm6-w34x'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-7845'
  - url: 'https://github.com/chatchat-space/Langchain-Chatchat/issues/5462'
  - url: >-
      https://github.com/3em0/cve_repo/blob/main/Langchain-Chatchat/Vuln-1-tobytes-Hash-Collision.md
  - url: 'https://github.com/chatchat-space/Langchain-Chatchat'
  - url: 'https://vuldb.com/submit/807794'
  - url: 'https://vuldb.com/vuln/361124'
  - url: 'https://vuldb.com/vuln/361124/cti'
tags:
  - osv
  - pip
epss: 0.0014
epssPercentile: 0.03707
ingestedAt: '2026-07-13T18:58:04.625Z'
---

## Overview

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.

## Affected packages

- `langchain-chatchat <= 0.3.1.3`

## Remediation

Refer to the advisory for the patched release.