CVE-2026-45666

The API /api/v1/notes/{note_id} endpoint lacks proper authorization checks, allowing authenticated users to retrieve notes belonging to other users by guessing or enumerating UUIDs. This results in unauthorized disclosure of potentially sensitive or private user data.

Details

• if notes is enabled from UI (Settings >> General >> Features >> Notes (Beta))
  • From API, attacker can access other user notes
• if notes is disabled from UI (Settings >> General >> Features >> Notes (Beta))
  • Then attacker can enable the notes from /api/config and access other user notes

PoC

• Step 1: Log in to the application as a valid user (User A).
  

• Step 2: Intercept or inspect the response from the endpoint GET /api/config.
  

• Step 3: Observe the field "enable_notes": false in the JSON response.

• Step 4: Manually change "enable_notes" to true using browser DevTools or by intercepting and modifying the response via a proxy like Burp Suite. (Please note, the occurrence of this API comes twice, hence modification needs to be made twice as well.)
  

• Step 5: Observe the loaded frontend application; the previously hidden notes form will now be visible.
  

• Step 6: Again, click on any note, intercept the request, and Replace the note_id in the URL with a different note ID known to belong to another user (e.g., by guessing or bruteforcing).
• Step 7: Send the modified request while remaining logged in as User A.
• Step 8: Observe that the server returns the content of another user's note, confirming unauthorized access.
  
  

Resolution

Fixed in commit de3317e26, first released in v0.8.11 (Mar 2026). All per-id note endpoints (GET /api/v1/notes/{id}, POST /api/v1/notes/{id}/update, POST /api/v1/notes/{id}/access/update, deletion) now enforce ownership: the handler fetches the note, then requires the caller to be admin, the note owner, or have an AccessGrants grant for the appropriate permission (read for retrieval, write for mutation). A non-owner with no grant receives 403.

Users on >= 0.8.11 are not affected.

1. Unauthorized access to user-created notes
2. Possible exposure of confidential or sensitive uploaded data
3. Violation of user privacy and data isolation
4. High risk of legal or compliance breaches in regulated environments

CVE-2026-45666 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.8.11); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-45666? CVE-2026-45666 is a medium-severity security vulnerability in open-webui (pip), affecting versions <= 0.8.10. It is fixed in 0.8.11.
2. How severe is CVE-2026-45666? CVE-2026-45666 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of open-webui are affected by CVE-2026-45666? open-webui (pip) versions <= 0.8.10 is affected.
4. Is there a fix for CVE-2026-45666? Yes. CVE-2026-45666 is fixed in 0.8.11. Upgrade to this version or later.
5. Is CVE-2026-45666 exploitable, and should I be worried? Whether CVE-2026-45666 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-45666 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-45666? Upgrade open-webui to 0.8.11 or later.