CVE-2026-51883

Deferred Deferred - Pending Action

BaseFortify

Publication date: 2026-10-01

Last updated on: 2026-10-05

Assigner: MITRE

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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-10-01

Last Modified

2026-10-05

Generated

2026-10-19

AI Q&A

2026-10-02

EPSS Evaluated

2026-10-18

NVD

CVE-2026-51883

EUVD

EUVD-2026-91122

Affected Vendors & Products

Vendor	Product	Version / Range
n/a	n/a	n/a

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-22	The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Attack-Flow Graph

Executive Summary

The vulnerability in Langchain-Chatchat versions 0.3.0 and 0.3.1 allows an attacker to use path traversal sequences like ..\ in the knowledge_base_name parameter. This lets them write knowledge base content to any location outside the intended root directory.

Detection Guidance

Check Langchain-Chatchat logs for unusual file write operations or path traversal attempts in the knowledge_base_name parameter. Monitor for files created outside the expected knowledge base directory structure.

Impact Analysis

An attacker could overwrite critical system files, inject malicious content, or disrupt the application by writing files to unauthorized locations. This may lead to data corruption, unauthorized access, or denial of service.

Compliance Impact

This vulnerability could potentially violate compliance with standards like GDPR or HIPAA by allowing unauthorized access or modification of sensitive data stored in knowledge bases. Unrestricted path traversal may lead to data leaks or unauthorized data manipulation, which are critical violations under these regulations.

Mitigation Strategies

Upgrade Langchain-Chatchat to a patched version if available. Restrict file write permissions to the knowledge base directory. Validate and sanitize all inputs for the knowledge_base_name parameter to prevent path traversal sequences.

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