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Public proof of concept

CVE-2026-51884

Path Traversal Allowing Arbitrary File Write in Langchain Chatchat Temporary Upload Endpoint

A public proof of concept exists; no exploitation attested.

  • Published2026-10-01
  • WeaknessCWE-22

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2026-10-0122:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-51884?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-51884?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-51884 yet.

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2026-10-01
Last Modified
2026-10-05
NVD status
Deferred

Frequently asked questions

What is CVE-2026-51884?

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.

Is CVE-2026-51884 actively exploited?

A proof-of-concept exploit exists for CVE-2026-51884, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-51884?

CVE-2026-51884 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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