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

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...

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...

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 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-2026-12284: 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...

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...

CVE-2026-75025

Mattermost Desktop App versions up to and including 6.2 are affected by a restriction flaw: server-rendered content was not sufficiently restricted from accessing local or private network resources from the desktop client. The issue was rated CVSS 3.1: 4.7 (MEDIUM) with a changed scope and low co...

CVE-2026-75025 Mattermost Desktop local network access from server-rendered content

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 Mattermost Desktop local network access from server-rendered content

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...

EUVD-2026-60543

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 =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 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...