| Component | LangChain |
| Severity | critical (CVSS 9.1) |
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| 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 creation and document upload interfaces in Langchain-Chatchat 0.3.0;0.3.1 is vulnerable to path traversal. An attacker can inject path traversal sequences (such as `..\`) into the `knowledge_base_name` parameter to write knowledge base content to arbitrary locations outside the configured knowledge base root 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-2026-51883
- https://gist.github.com/Ro1ME/30f5139a2920bf7075299a33eb1690f2
- https://github.com/chatchat-space/Langchain-Chatchat/issues/5467
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