GHSA-jgj3-r8hr-9pjw CVE-2026-44571 PYSEC-2026-2739

Open WebUI's Improper Authorization in Standard Channels Allows Message Updates with Read Permission

Medium PyPI

Severity: 6.5 / 10; Medium · CVSS 3.1
Exploit chance (EPSS): 0.28%; Chance of exploitation in the next 30 days. Higher than 20.18% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-862 Missing Authorization
Fix: 0.8.6; Upgrade open-webui to this version or later

Description

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

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

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

Create User A

Create User B

As the administrator, create a new channel

As User A, post a new message in the channel

As User B, edit User A’s message

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

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

Affected versions

PyPI

Package	Vulnerable	Fixed in
open-webui	`< 0.8.6`	`0.8.6`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

open-webui PyPI → `0.8.6`

pip

pip install --upgrade "open-webui>=0.8.6"

poetry

poetry add "open-webui>=0.8.6"

uv

uv add "open-webui>=0.8.6"

Severity breakdown

CVSS 3.1 6.5

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
Availability: None

Weakness

CWE-862: Missing Authorization

The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

How to prevent it

Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

References

Advisories

Packages

Timeline

May 11, 2026 Published
Jul 13, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-wvm9-9g5j-623f Open WebUI: Users denied by the OAuth role policy can still sign in via token exchange	Medium	Also affects open-webui
GHSA-4qg5-cxx4-g927 Open WebUI: Users denied by the OAuth domain allowlist or role policy can still sign in via token exchange	Medium	Also affects open-webui
GHSA-jqhh-cjmq-vmv6 Open WebUI: Any authenticated user can hang the server via a cyclic chat message history	Medium	Also affects open-webui
GHSA-5x7x-4c3c-qf5w Open WebUI: Server-side fetches reach blocked and internal hosts via unvalidated HTTP redirect targets	Medium	Also affects open-webui
GHSA-3cgp-3cqx-j8w2 Open WebUI: Any authenticated user can hang the server via message deletion in a cyclic chat tree	Medium	Also affects open-webui
GHSA-34r3-9m95-vq73 Open WebUI: Any authenticated user can reach the Azure platform channel via server-side web fetch	High	Also affects open-webui
GHSA-2724-6cpj-gf3v Open WebUI: Non-admin users can delete admin-owned external knowledge connections via knowledge base deletion	High	Also affects open-webui
GHSA-3pf7-q2g3-wj28 Open WebUI: Any authenticated user can inject chats into another user's folder via chat completions	Medium	Also affects open-webui

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