CVE-2026-75588

Mattermost Desktop App versions =6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme...

CVE-2026-12284

Mattermost Desktop App versions =6.2 6.2.2.0 fails to validate the IPC sender in the leaveCall handler which allows a malicious or compromised Mattermost server or a user with script access to a connected server view to disconnect an active call belonging to a different connected server via the...

CVE-2026-12284 Mattermost Desktop App Missing IPC Sender Validation in Calls Leave Handler

Mattermost Desktop App versions =6.2 6.2.2.0 fails to validate the IPC sender in the leaveCall handler which allows a malicious or compromised Mattermost server or a user with script access to a connected server view to disconnect an active call belonging to a different connected server via the...

CVE-2026-12284

Mattermost Desktop App versions

EUVD-2026-81680

Mattermost Desktop App versions =6.2 6.2.2.0 fails to validate the IPC sender in the leaveCall handler which allows a malicious or compromised Mattermost server or a user with script access to a connected server view to disconnect an active call belonging to a different connected server via the...

CVE-2026-12284 Mattermost Desktop App Missing IPC Sender Validation in Calls Leave Handler

Mattermost Desktop App versions =6.2 6.2.2.0 fails to validate the IPC sender in the leaveCall handler which allows a malicious or compromised Mattermost server or a user with script access to a connected server view to disconnect an active call belonging to a different connected server via the...

EUVD-2026-81678

Mattermost Desktop App versions =6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme...

CVE-2026-75588 Mattermost Desktop App plugin popout scheme validation bypass

Mattermost Desktop App versions =6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme...

CVE-2026-75588 Mattermost Desktop App plugin popout scheme validation bypass

Mattermost Desktop App versions =6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme...

CVE-2026-75588 Mattermost Desktop App plugin popout scheme validation bypass

Mattermost Desktop App versions =6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme...

CVE-2026-75588

Mattermost Desktop App versions

PT-2026-94361

Name of the Vulnerable Software and Affected Versions Mattermost Desktop App versions prior to 6.2.2.0 Description The application fails to validate the Inter-Process Communication IPC sender within the leaveCall handler. This allows a compromised Mattermost server or a user with script access to...

CVE-2026-12284: Origin Validation Error

Mattermost Desktop App versions =6.2 6.2.2.0 fails to validate the IPC sender in the leaveCall handler which allows a malicious or compromised Mattermost server or a user with script access to a connected server view to disconnect an active call belonging to a different connected server via the...

CVE-2026-75588: Improper Validation of Specified Type of Input

Mattermost Desktop App versions =6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme...

PT-2026-94365

Name of the Vulnerable Software and Affected Versions Mattermost Desktop App versions prior to 6.2.2.0 Description The application fails to validate the URL scheme when verifying if a target URL is internal to the connected server. This allows a network-positioned attacker to load a plugin popout...

CVE-2026-75025

Mattermost Desktop App versions =6.2 6.2.2.0 Fixed an issue where Mattermost Desktop did not sufficiently restrict server-rendered content from accessing local or private network resources. Thanks to game0v3r for contributing to this improvement under the Mattermost responsible disclosure policy...

EUVD-2026-80939

Mattermost Desktop App versions =6.2 6.2.2.0 Fixed an issue where Mattermost Desktop did not sufficiently restrict server-rendered content from accessing local or private network resources. Thanks to game0v3r for contributing to this improvement under the Mattermost responsible disclosure policy...

PT-2026-93898

Name of the Vulnerable Software and Affected Versions Mattermost Desktop App versions prior to 6.2.2.0 Description The application does not sufficiently restrict server-rendered content from accessing local or private network resources. Recommendations Update to version 6.2.2.0...

CVE-2026-75025: Origin Validation Error

Mattermost Desktop App versions =6.2 6.2.2.0 Fixed an issue where Mattermost Desktop did not sufficiently restrict server-rendered content from accessing local or private network resources. Thanks to game0v3r for contributing to this improvement under the Mattermost responsible disclosure policy...

CVE-2026-75587

Mattermost Desktop App versions =6.2 6.2.2.0 fail to redact the pre-auth secret when generating a diagnostics report, which allows a local attacker with access to a user's diagnostics report or log files to obtain the plaintext pre-auth secret configured for a connected server via inspecting the...