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.
Metrics
Affected Vendors & Products
References
History
Fri, 15 May 2026 23:15:00 +0000
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ssvc
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Fri, 15 May 2026 22:45:00 +0000
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Open-webui
Open-webui open-webui |
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Open-webui
Open-webui open-webui |
Fri, 15 May 2026 21:00:00 +0000
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| Description | 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. | |
| Title | Open WebUI: Cross-User File Access via Unchecked file_id in Folder Knowledge and Knowledge-Base Attach Endpoints | |
| Weaknesses | CWE-639 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-05-15T22:21:36.768Z
Reserved: 2026-05-12T01:48:40.451Z
Link: CVE-2026-45402
Updated: 2026-05-15T22:17:52.363Z
Status : Received
Published: 2026-05-15T21:16:38.273
Modified: 2026-05-15T23:16:21.470
Link: CVE-2026-45402
No data.
OpenCVE Enrichment
Updated: 2026-05-15T22:30:06Z