GHSA-JGJ3-R8HR-9PJW

Vulnerability from github – Published: 2026-05-11 14:05 – Updated: 2026-05-19 15:57
VLAI
Summary
Open WebUI's Improper Authorization in Standard Channels Allows Message Updates with Read Permission
Details

Vulnerability Description

In standard channels (i.e., channels whose channel.type is neither group nor dm), the endpoint

POST /api/v1/channels/{channel_id}/messages/{message_id}/update can be accessed with read permission only.

When 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.

As a result, unauthorized modification of other users’ messages is possible.

Attack Prerequisites

  • The attacker is an authenticated user (role user or higher)
  • The target channel is a standard channel (i.e., not group or dm)
  • access_control is None or allows read access
  • The attacker can obtain the target message_id (e.g., via the channel’s message list)

Attack Scenario

  1. The attacker (User B) retrieves another user’s message_id from the message list in a standard channel

  2. The attacker sends a request to

    POST /api/v1/channels/{channel_id}/messages/{message_id}/update

  3. The message authored by another user (User A) is successfully updated

Potential Impact

  • Unauthorized modification of other users’ messages (violation of data integrity)

Steps to Reproduce

  1. Log in as an administrator

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  1. Create User A

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  1. Create User B

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  1. Log in as User A

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  1. Log in as User B

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  1. As the administrator, create a new channel

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  1. As User A, post a new message in the channel

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  1. As User B, edit User A’s message

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  1. Confirm that User A’s message has been modified without authorization

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Affected Files and Line Numbers

  • backend/open_webui/routers/channels.py:1417–1460

    The authorization check in update_message_by_id allows access with read permission

  • backend/open_webui/utils/access_control.py:124–135

    When access_control=None and strict=True, read access is permitted

  • backend/open_webui/models/messages.py:341–358

    The update logic does not enforce any message ownership check

Recommended Mitigation

Update the condition in

backend/open_webui/routers/channels.py:1451–1456

by changing the permission check from read to write, so that only administrators, message owners, or users with write permission can update messages.

Proposed Changes

  • For standard channels, change the update permission requirement from

    has_access(..., type="read") to has_access(..., type="write")

  • Preserve the existing ownership check (message.user_id == user.id)

AI Usage

  • Translation from Japanese to English
  • CWE classification and assessment
  • Affected Files and Line Numbers
Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.8.5"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.8.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44571"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-862"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-11T14:05:24Z",
    "nvd_published_at": "2026-05-15T22:16:53Z",
    "severity": "MODERATE"
  },
  "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\u2019 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\u2019s message list)\n\n\n\n## Attack Scenario\n\n1. The attacker (User B) retrieves another user\u2019s `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\u2019 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\u2019s 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\u2019s 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\u20131460`\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\u2013135`\n    \n    When `access_control=None` and `strict=True`, **read** access is permitted\n    \n- `backend/open_webui/models/messages.py:341\u2013358`\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\u20131456`\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",
  "id": "GHSA-jgj3-r8hr-9pjw",
  "modified": "2026-05-19T15:57:52Z",
  "published": "2026-05-11T14:05:24Z",
  "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI\u0027s Improper Authorization in Standard Channels Allows Message Updates with Read Permission"
}



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