CVE-2026-44571 — Open WebUI: Improper Authorization in Standard Channels Allows Message Updates with Read Permission

Affected: open-webui

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.8.6, 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. This vulnerability is fixed in 0.8.6.

PYSEC-2026-2739 — Open WebUI's Improper Authorization in Standard Channels Allows Message Updates with Read Permission

Affected: PyPI: open-webui

## 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.

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## 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

2. Create User A

<img width="3346" height="788" alt="image" src="h…

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CVE-2026-44571 — Open WebUI: Improper Authorization in Standard Channels Allows Message Updates with Read Permission

PYSEC-2026-2739 — Open WebUI's Improper Authorization in Standard Channels Allows Message Updates with Read Permission