CVE-2026-51883
CriticalCVSS 9.1Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
Path traversal vulnerability in knowledge base creation and document upload interfaces in Langchain-Chatchat 0.3.0 and 0.3.1. An attacker can inject path traversal sequences (such as `..\`) into the `knowledge_base_name` parameter to write knowledge base content outside the configured root directory.
Risk Assessment
Ability to write outside the allowed directory can lead to overwriting system or application files, potentially resulting in system integrity compromise or takeover.
Recommendation
Update Langchain-Chatchat to a patched version. Additionally, validate the `knowledge_base_name` parameter and use safe paths.
Other vulnerabilities in Langchain-Chatchat
See all- CVE-2026-51884Critical
Path traversal vulnerability in the /knowledge_base/upload_temp_docs endpoint in Langchain Chatchat 0.3.1. An attacker can write files to arbitrary locations on the server using malicious filenames, bypassing temporary directory restrictions.
- CVE-2026-51882Low risk· EPSS 3%
Path traversal vulnerability in the OpenAI-compatible file upload endpoint `/v1/files` in Langchain-Chatchat 0.3.0. An attacker can write files to arbitrary locations outside the `openai_files` directory using malicious filenames.
- CVE-2026-7847Low
A vulnerability in Langchain-Chatchat up to version 0.3.1.3 in the _get_file_id function of the Uploaded File Handler component generates insufficiently random values, potentially allowing an attacker to predict file IDs. The attack requires local network access and is considered difficult.
- CVE-2026-7846Low
In Langchain-Chatchat up to version 0.3.1.3, the OpenAI-Compatible File Upload API has a time-of-check time-of-use (TOCTOU) vulnerability when processing the file.filename argument. The exploit is public and the project has not responded.
- CVE-2026-7845Low
In Langchain-Chatchat up to 0.3.1.3, a vulnerability was found in the function PIL.Image.tobytes of dialogue.py in the Vision Chat Paste Image Handler component. Manipulation of the paste_image.image_data argument leads to use of weak hash. Local network access is required and the attack is difficult.
- CVE-2026-7844Medium
In Langchain-Chatchat up to version 0.3.1.3, a vulnerability involves missing authentication in the Compatible File Service component. Functions files/list_files/retrieve_file/retrieve_file_content/delete_file in openai_routes.py lack authentication. The attack requires local network access. The exploit is public.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS