{"id":"PYSEC-2026-2739","summary":"Open WebUI's Improper Authorization in Standard Channels Allows Message Updates with Read Permission","details":"## Vulnerability Description\n\nIn standard channels (i.e., channels whose `channel.type` is neither `group` nor `dm`), the endpoint\n\n`POST /api/v1/channels/{channel_id}/messages/{message_id}/update` can be accessed with **read permission only**.\n\nWhen `access_control` is set to `None`, the authorization check `has_access(..., type=\"read\")` evaluates to `True`, allowing users who are **not the message owner** to update messages.\n\nAs a result, unauthorized modification of other users’ messages is possible.\n\n---\n\n## Attack Prerequisites\n\n- The attacker is an authenticated user (role `user` or higher)\n- The target channel is a standard channel (i.e., not `group` or `dm`)\n- `access_control` is `None` or allows `read` access\n- The attacker can obtain the target `message_id` (e.g., via the channel’s message list)\n\n\n\n## Attack Scenario\n\n1. The attacker (User B) retrieves another user’s `message_id` from the message list in a standard channel\n2. The attacker sends a request to\n    \n    `POST /api/v1/channels/{channel_id}/messages/{message_id}/update`\n    \n3. The message authored by another user (User A) is successfully updated\n\n\n\n## Potential Impact\n\n- Unauthorized modification of other users’ messages (violation of data integrity)\n\n\n# Steps to Reproduce\n\n1. Log in as an administrator\n\n\u003cimg width=\"3334\" height=\"1668\" alt=\"image\" src=\"https://github.com/user-attachments/assets/b20323d3-c050-4438-8912-193a417654bc\" /\u003e\n\n\n2. Create User A\n\n\u003cimg width=\"3346\" height=\"788\" alt=\"image\" src=\"https://github.com/user-attachments/assets/b9e4fb8a-b14e-4a4b-b012-02ccfba52fca\" /\u003e\n\n3. Create User B\n\n\u003cimg width=\"3354\" height=\"796\" alt=\"image\" src=\"https://github.com/user-attachments/assets/f3cf6892-e6c9-4778-b471-f1cc0deec6c8\" /\u003e\n\n\n4. Log in as User A\n\n\u003cimg width=\"3360\" height=\"1668\" alt=\"image\" src=\"https://github.com/user-attachments/assets/5264ee07-f5c5-4bbe-ad4f-da69fb540fc9\" /\u003e\n\n\n5. Log in as User B\n\n\u003cimg width=\"3354\" height=\"1670\" alt=\"image\" src=\"https://github.com/user-attachments/assets/f112f8e8-b3e2-4e65-b226-c7b6c986f3bb\" /\u003e\n\n\n6. As the administrator, create a new channel\n\n\u003cimg width=\"2582\" height=\"988\" alt=\"image\" src=\"https://github.com/user-attachments/assets/bc012d9a-f884-4c83-b6bb-d1e5399f61bb\" /\u003e\n\n\n7. As User A, post a new message in the channel\n\n\u003cimg width=\"2626\" height=\"962\" alt=\"image\" src=\"https://github.com/user-attachments/assets/d7ff12c2-fe17-44f0-aaf9-5ce2bac9a378\" /\u003e\n\n\n8. As User B, edit User A’s message\n\n\u003cimg width=\"2604\" height=\"958\" alt=\"image\" src=\"https://github.com/user-attachments/assets/8e19ec3e-fdda-4d36-acd5-f3e1fd3402dd\" /\u003e\n\n\n9. Confirm that User A’s message has been modified without authorization\n\n\u003cimg width=\"2378\" height=\"1976\" alt=\"image\" src=\"https://github.com/user-attachments/assets/6415fd41-ac68-4d42-83c9-6297caee1fb4\" /\u003e\n\n\n## Affected Files and Line Numbers\n\n- `backend/open_webui/routers/channels.py:1417–1460`\n    \n    The authorization check in `update_message_by_id` allows access with **read** permission\n    \n- `backend/open_webui/utils/access_control.py:124–135`\n    \n    When `access_control=None` and `strict=True`, **read** access is permitted\n    \n- `backend/open_webui/models/messages.py:341–358`\n    \n    The update logic does not enforce any message ownership check\n    \n\n## Recommended Mitigation\n\nUpdate the condition in\n\n`backend/open_webui/routers/channels.py:1451–1456`\n\nby changing the permission check from **`read`** to **`write`**, so that only administrators, message owners, or users with write permission can update messages.\n\n### Proposed Changes\n\n- For standard channels, change the update permission requirement from\n    \n    `has_access(..., type=\"read\")` to `has_access(..., type=\"write\")`\n    \n- Preserve the existing ownership check (`message.user_id == user.id`)\n\n## **AI Usage**\n\n- Translation from Japanese to English\n- CWE classification and assessment\n- Affected Files and Line Numbers","aliases":["CVE-2026-44571","GHSA-jgj3-r8hr-9pjw"],"modified":"2026-07-13T16:32:16.498365824Z","published":"2026-07-13T15:15:43.914937Z","references":[{"type":"WEB","url":"https://github.com/open-webui/open-webui/security/advisories/GHSA-jgj3-r8hr-9pjw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44571"},{"type":"PACKAGE","url":"https://github.com/open-webui/open-webui"},{"type":"PACKAGE","url":"https://pypi.org/project/open-webui"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-jgj3-r8hr-9pjw"}],"affected":[{"package":{"name":"open-webui","ecosystem":"PyPI","purl":"pkg:pypi/open-webui"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.8.6"}]}],"versions":["0.1.124","0.1.125","0.2.0","0.2.1","0.2.2","0.2.3","0.2.4","0.2.5","0.3.0","0.3.1","0.3.10","0.3.12","0.3.13","0.3.14","0.3.15","0.3.16","0.3.17","0.3.17.dev2","0.3.17.dev3","0.3.17.dev4","0.3.17.dev5","0.3.18","0.3.19","0.3.2","0.3.20","0.3.21","0.3.22","0.3.23","0.3.24","0.3.25","0.3.26","0.3.27","0.3.27.dev1","0.3.27.dev2","0.3.27.dev3","0.3.28","0.3.29","0.3.3","0.3.30","0.3.30.dev1","0.3.30.dev2","0.3.31","0.3.31.dev1","0.3.32","0.3.33","0.3.33.dev1","0.3.34","0.3.35","0.3.4","0.3.5","0.3.6","0.3.7","0.3.8","0.3.9","0.4.0","0.4.0.dev1","0.4.0.dev2","0.4.1","0.4.2","0.4.3","0.4.4","0.4.5","0.4.6","0.4.6.dev1","0.4.7","0.4.8","0.5.0","0.5.0.dev1","0.5.0.dev2","0.5.1","0.5.10","0.5.11","0.5.12","0.5.13","0.5.14","0.5.15","0.5.16","0.5.17","0.5.18","0.5.19","0.5.2","0.5.20","0.5.3","0.5.3.dev1","0.5.4","0.5.5","0.5.6","0.5.7","0.5.8","0.5.9","0.6.0","0.6.1","0.6.10","0.6.11","0.6.12","0.6.13","0.6.14","0.6.15","0.6.16","0.6.18","0.6.19","0.6.2","0.6.20","0.6.21","0.6.22","0.6.23","0.6.24","0.6.25","0.6.26","0.6.26.dev1","0.6.27","0.6.28","0.6.29","0.6.3","0.6.30","0.6.31","0.6.32","0.6.33","0.6.34","0.6.35","0.6.36","0.6.37","0.6.38","0.6.39","0.6.4","0.6.40","0.6.41","0.6.42","0.6.43","0.6.5","0.6.6","0.6.6.dev1","0.6.7","0.6.8","0.6.9","0.7.0","0.7.1","0.7.2","0.8.0","0.8.1","0.8.2","0.8.3","0.8.4","0.8.5"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/open-webui/PYSEC-2026-2739.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"}]}