| Component | LangChain |
| Severity | critical (CVSS 9.8) |
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| Published (NVD) | 2026-10-01 |
| Last modified | 2026-10-05 |
| Affected versions | not published yet, see the advisory |
| Fixed in | see the vendor advisory |
| Weakness | CWE-22 |
| CISA KEV | not listed |
NVD description
The /knowledge_base/upload_temp_docs temporary document upload endpoint in Langchain Chatchat 0.3.1 is vulnerable to path traversal. By crafting malicious filenames, an attacker can write files to arbitrary locations on the server, bypassing the intended restrictions on the temporary directory.
What to do
- NVD lists no fixed version yet: follow the vendor advisory below and keep LangChain off the public internet until a fix ships.
- Do not expose the component's API or UI to the internet without authentication in front of it.
Sources
- NVD: CVE-2026-51884
- https://gist.github.com/Ro1ME/da028c9ce13dd888e265b9bef01d6eca
- https://github.com/chatchat-space/Langchain-Chatchat/issues/5466
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