open-webui Open WebUI up to 0.9.4 folders.py authorization

Summaryinfo

A vulnerability has been found in open-webui Open WebUI up to 0.9.4 and classified as critical. This issue affects some unknown processing of the file backend/open_webui/routers/folders.py. Performing a manipulation results in authorization. This vulnerability is cataloged as CVE-2026-45402. It is possible to initiate the attack remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, was found in open-webui Open WebUI up to 0.9.4. This affects an unknown part of the file backend/open_webui/routers/folders.py. The manipulation with an unknown input leads to a authorization vulnerability. CWE is classifying the issue as CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, multiple endpoints accept a user-supplied file_id and attach the referenced file to a resource the caller controls (folder knowledge, knowledge-base contents) without verifying that the caller owns or has been granted access to the file. The file's content then becomes reachable through the downstream RAG / file-content paths, allowing any authenticated user to exfiltrate any other user's private file — and on the knowledge-base path, also to overwrite it — given knowledge of the file's UUID. This affects backend/open_webui/routers/folders.py (POST /api/v1/folders/{id}/update), backend/open_webui/routers/knowledge.py (add_file_to_knowledge_by_id), and backend/open_webui/routers/knowledge.py (add_files_to_knowledge_by_id_batch). This vulnerability is fixed in 0.9.5.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-45402 since 05/12/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details are known, but no exploit is available.

Upgrading to version 0.9.5 eliminates this vulnerability.

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Productinfo

Vendor

• open-webui

Name

• Open WebUI

Version

• 0.9.0
• 0.9.1
• 0.9.2
• 0.9.3
• 0.9.4

CPE 2.3info

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CPE 2.2info

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