CVE-2026-28759 Insufficient authorization in shared channel membership sync allows remote cluster to remove users from arbitrary channels

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13, 11.4.x = 11.4.3 fail to validate that a remote cluster has access to a channel before processing membership removal requests during shared channel membership sync, which allows a malicious remote cluster to remove any user from any channel,...

CVE-2026-28759

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13, 11.4.x = 11.4.3 fail to validate that a remote cluster has access to a channel before processing membership removal requests during shared channel membership sync, which allows a malicious remote cluster to remove any user from any channel,...

CVE-2026-28759 Insufficient authorization in shared channel membership sync allows remote cluster to remove users from arbitrary channels

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13, 11.4.x = 11.4.3 fail to validate that a remote cluster has access to a channel before processing membership removal requests during shared channel membership sync, which allows a malicious remote cluster to remove any user from any channel,...

CVE-2026-28759

Mattermost multiple releases (11.4.x <= 11.4.3, 11.5.x <= 11.5.1, 10.11.x

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Vulnerabilities exist in Mattermost versions 11.5.1 and earlier of the 11.5.x series, as well as versions 10.11.13 and earlier of the 10.11.x series, and 11.4.3 and earlier of the 11.4.x series. Thes...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Versions of Mattermost 11.5.1 and earlier, including 11.5.x, have security vulnerabilities. These vulnerabilities stem from the lack of verification of channel members when processing AI-assisted...

PT-2026-41655

Name of the Vulnerable Software and Affected Versions Mattermost versions 11.5.x through 11.5.1 Description An issue exists where channel membership is not verified during the processing of AI-assisted message rewrites. This allows an authenticated attacker to read the content of threads in priva...

CVE-2026-44571

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/channelid/messages/messageid/update can be accessed with read...

CVE-2026-44571

CVE-2026-44571 concerns the Open WebUI platform. In standard channels, the endpoint POST /api/v1/channels/{channel_id}/messages/{message_id}/update could be invoked with only read permission if access_control is None, allowing unauthorized users to modify other users’ messages. The issue is fixed...

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

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/channelid/messages/messageid/update can be accessed with read...

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

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/channelid/messages/messageid/update can be accessed with read...

CVE-2026-44571

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/channelid/messages/messageid/update can be accessed with read...

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

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/channelid/messages/messageid/update can be accessed with read...

EUVD-2026-30655

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/channelid/messages/messageid/update can be accessed with read...

CVE-2026-45386

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, Pin/Unpin is a write operation modifies the message's ispinned , pinnedby, pinnedat fields, but in standard channels it only checks read permission, allowing users with read-only...

CVE-2026-45385

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, an IDOR vulnerability exists in the Channels feature of Open WebUI, allowing any channel member to modify messages sent by other members including administrators within the same...

CVE-2026-44569

Open WebUI CVE-2026-44569 describes an IDOR in the channel messages management system. Before version 0.6.19, authenticated users could modify or delete any message in channels they can read because message ownership validation was missing in the backend update/delete endpoints, even though the f...

CVE-2026-44569 Open WebUI: Insecure Message Access Breaks Authorization

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.6.19, there's an IDOR in the channels message management system that allows authenticated users to modify or delete any message within channels they have read access to. The vulnerability...

CVE-2026-45386 Open WebUI: An IDOR vulnerability exists in the pin_channel_message API endpoint

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, Pin/Unpin is a write operation modifies the message's ispinned , pinnedby, pinnedat fields, but in standard channels it only checks read permission, allowing users with read-only...

CVE-2026-45385

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, an IDOR vulnerability exists in the Channels feature of Open WebUI, allowing any channel member to modify messages sent by other members including administrators within the same...