CVE-2026-44559 Open WebUI: Missing Access Check on Channel Members Endpoint for Standard Channels

Medium 4.3 Published 15 May 2026 Updated 15 May 2026

Authenticated users can enumerate members of private channels due to missing access checks, exposing user lists.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-44559?

CVE-2026-44559 is a medium-severity missing authorization vulnerability in Openwebui Open Webui, published on 15 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the GET /api/v1/channels/{id}/members endpoint only checks membership for group and dm channel types (lines 467-469). For standard channels — including private ones — there is no channel_has_access check before returning the member list. Any authenticated user who knows a private channel's UUID can enumerate all users with access to that channel. This vulnerability is fixed in 0.9.0.

Weakness: CWE-862

Which versions are affected by CVE-2026-44559?

3 open source packages ship an affected version, including open-webui. It affects 1 product.

Package	Affected	Fixed in
`open-webui` PyPI	All versions	`0.9.0`
`open-webui` PyPI	All versions	`0.9.0`
`open-webui` PyPI	All versions	`0.9.0`

Products include Openwebui Open Webui.

How do I fix CVE-2026-44559?

Upgrade open-webui to 0.9.0 or later.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-44559 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44559 exists.

All Openwebui Open Webui vulnerabilities

Sources

Also known as GHSA-c7wp-3qh5-55pv, PYSEC-2026-2720.