CVE-2026-45666: Open WebUI Indirect Object Reference (IDOR) Vulnerability in User Notes
Summary
CVE-2026-45666: Open WebUI has an Indirect Object Reference (IDOR) in user notes. Affects open-webui versions < 0.8.11. Fixed in 0.8.11. How to fix ↓
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Background
Open WebUI is an open-source web application that provides a user-friendly interface for managing various functionalities. It allows users to create and manage notes, among other features. However, a significant vulnerability has been identified in the notes management system, specifically related to authorization checks, which can lead to unauthorized access to user data.
Vulnerability Detail
The vulnerability arises from the API endpoint /api/v1/notes/{note_id}, which lacks proper authorization checks. Authenticated users can exploit this weakness to access notes belonging to other users by guessing or enumerating UUIDs. This can lead to unauthorized disclosure of sensitive information, violating user privacy and potentially breaching legal compliance. The issue is exacerbated by the ability for users to enable notes even when the feature is disabled, further increasing the risk of unauthorized access.
How To Fix
Latest published version: 0.12.3 as of 22 Oct 2026
pip install --upgrade "open-webui==0.12.3"Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
0.8.11
This is the first release that contains the fix.
pip install --upgrade "open-webui==0.8.11"Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can restrict access to the notes feature by ensuring that only trusted users have access to the application. However, this does not fully mitigate the risk and is not a substitute for applying the patch.
Conclusion
The CVE-2026-45666 vulnerability in Open WebUI poses a significant risk by allowing unauthorized access to user notes. It is crucial for users to update to version 0.8.11 or later to ensure proper authorization checks are in place and protect sensitive user data.
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FAQ
CVE-2026-45666 is a vulnerability in Open WebUI that allows unauthorized access to user notes due to insufficient authorization checks.
You can check if your application is affected by using the Vulert playground at Vulert Scanner, which monitors open-source vulnerabilities without requiring signup.
The risks include unauthorized access to sensitive user data, potential legal compliance breaches, and violation of user privacy.
You can update to the patched version by running 'pip install --upgrade open-webui' in your terminal.
While the best solution is to update, you can temporarily restrict access to the notes feature to trusted users, but this is not a complete fix.
References
Related vulnerabilities
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