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 versions

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-2026-81680

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...

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 versions

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: 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...

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...

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...

CVE-2026-75587

Mattermost Desktop App versions

CVE-2026-75587 Plaintext pre-auth secret exposure via Desktop App diagnostics report

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...

PT-2026-76874

Name of the Vulnerable Software and Affected Versions Mattermost Desktop App versions prior to 6.2.2.0 Description The application fails to redact the pre-auth secret during the generation of a diagnostics report. A local attacker with access to the user's log files or diagnostics report can obta...

CVE-2026-75587: Exposure of Sensitive Information to an Unauthorized Actor

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...

CVE-2026-8075

Mattermost Desktop App versions =6.2 5.5.13 6.0.2.0 fail to properly null check when checking for headers in the Mattermost Desktop App which allows any user to crash another channel members Desktop App via posting a malicious link with an embedded image that misses one of those headers. Mattermo...

CVE-2026-8075

Mattermost Desktop App versions =6.2 5.5.13 6.0.2.0 fail to properly null check when checking for headers in the Mattermost Desktop App which allows any user to crash another channel members Desktop App via posting a malicious link with an embedded image that misses one of those headers. Mattermo...