CVE-2026-70488

Received Received - Intake

Authorization Bypass in Open WebUI Knowledge Base

Publication date: 2026-08-04

Last updated on: 2026-08-04

Assigner: GitHub, Inc.

Description

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.6 until 0.11.0, the sync cleanup endpoint authorized write access to the knowledge base in the URL but then acted on directory and file ids supplied in the request body without checking that those objects belonged to that knowledge base. A user with write access to one knowledge base could delete directories and remove file embeddings from another knowledge base, causing documents to drop out of retrieval results and breaking chat-with-file for targeted documents without disclosing contents. This issue is fixed in 0.11.0.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-04

Last Modified

2026-08-04

Generated

2026-08-05

AI Q&A

2026-08-05

EPSS Evaluated

N/A

NVD

CVE-2026-70488

EUVD

EUVD-2026-52899

Affected Vendors & Products

Vendor	Product	Version / Range
open_webui	open_webui	0.11.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
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.
CWE-863	The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Attack-Flow Graph

Executive Summary

Open WebUI versions 0.9.6 to 0.11.0 had a flaw in the sync cleanup endpoint. The endpoint allowed write access to a knowledge base via URL but did not verify if directory or file IDs in the request body belonged to that specific knowledge base. This let users with write access to one knowledge base delete directories or remove file embeddings from another, causing documents to disappear from retrieval results and breaking the chat-with-file feature without exposing content.

Impact Analysis

If you use Open WebUI versions 0.9.6 to 0.11.0, an attacker with write access to one knowledge base could delete files or directories in another knowledge base. This disrupts document retrieval and breaks the chat-with-file feature for affected documents, leading to data unavailability without exposing the actual content.

Compliance Impact

This vulnerability could impact compliance by causing unauthorized data loss or unavailability. For GDPR, it may affect data integrity and availability requirements. For HIPAA, it could disrupt access to protected health information, potentially violating integrity and availability rules. However, no evidence suggests data exposure occurred.

Mitigation Strategies

Upgrade Open WebUI to version 0.11.0 or later to address the vulnerability. Ensure only authorized users have write access to knowledge bases.

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