Memory Allocation with Excessive Size Value

Overview github.com/mattermost/mattermost/server/channels/app is a private-cloud Slack alternative Affected versions of this package are vulnerable to Memory Allocation with Excessive Size Value in the integration action endpoints. An attacker can exhaust server memory and disrupt service...

EUVD-2026-12409

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID:...

Missing Authorization

Overview Affected versions of this package are vulnerable to Missing Authorization in the channel search API endpoint. An attacker can access information about all public channels within a private team by querying the API after being removed from the team. Remediation Upgrade...

Mattermost allows a removed team member to enumerate all public channels within a private team

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint. Mattermost Advisory ID:...

GHSA-679F-WMRG-QF57 Mattermost allows a removed team member to enumerate all public channels within a private team

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint. Mattermost Advisory ID:...

Improper Validation of Specified Type of Input

Overview github.com/mattermost/mattermost/server/channels/app is a private-cloud Slack alternative Affected versions of this package are vulnerable to Improper Validation of Specified Type of Input due to improper validation of User-Agent header tokens. An attacker can trigger a panic in the...

CVE-2026-21386

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to use consistent error responses when handling the /mute command which allows an authenticated team member to enumerate private channels they are not authorized to know about via differing error messages for nonexisten...

CVE-2026-21386

CVE-2026-21386 (Mattermost): The Mattermost server variants 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, and 10.11.x

CVE-2026-21386

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to use consistent error responses when handling the /mute command which allows an authenticated team member to enumerate private channels they are not authorized to know about via differing error messages for nonexisten...

CVE-2026-21386 Private channel enumeration via /mute slash command

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to use consistent error responses when handling the /mute command which allows an authenticated team member to enumerate private channels they are not authorized to know about via differing error messages for nonexisten...

CVE-2026-21386 Private channel enumeration via /mute slash command

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to use consistent error responses when handling the /mute command which allows an authenticated team member to enumerate private channels they are not authorized to know about via differing error messages for nonexisten...

CVE-2026-2458

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID:...

CVE-2026-2458

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID:...

CVE-2026-2458 Unauthorized channel enumeration in private teams after member removal

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID:...

CVE-2026-2458 Unauthorized channel enumeration in private teams after member removal

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID:...

Models Are Applying to Be the Face of AI Scams

Dozens of Telegram channels reviewed by WIRED include job listings for “AI face models.” The mostly women who land these gigs are likely being used to dupe victims out of their money...

PT-2026-25684

Mattermost allows a removed team member to enumerate all public channels within a private team in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. If this is causi...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Versions of Mattermost such as 10.11.10 and earlier, including 10.11.x, have security vulnerabilities. These vulnerabilities stem from the failure to invalidate cached preview data of fixed links whe...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Versions of Mattermost such as 11.3.0 and earlier 11.3.x series, 11.2.2 and earlier 11.2.x series, as well as 10.11.10 and earlier 10.11.x series, have security vulnerabilities. These vulnerabilities...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Versions of Mattermost such as 11.3.0 and earlier 11.3.x series, 11.2.2 and earlier 11.2.x series, as well as 10.11.10 and earlier 10.11.x series, have security vulnerabilities. These vulnerabilities...