CVE-2026-3495

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to escape some variables that could contain malicious content during error page composition which allows an attacker with access to edit some site configuration to execute some malicious code via injecting some JS as part of those...

GHSA-JX93-PF6X-874R Mattermost doesn't escape some variables that could contain malicious content during error page composition

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to escape some variables that could contain malicious content during error page composition which allows an attacker with access to edit some site configuration to execute some malicious code via injecting some JS as part of those...

CVE-2026-6345

Mattermost advisory CVE-2026-6345 affects Mattermost versions 11.4.x ≤ 11.4.3, 11.5.x ≤ 11.5.1 and 10.11.x ≤ 10.11.13. The issue is described as failing to prevent disclosure of created user passwords during the Slack import process, which could allow a malicious actor to impersonate a user using...

CVE-2026-3495 Unescaped variables during error page composition

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to escape some variables that could contain malicious content during error page composition which allows an attacker with access to edit some site configuration to execute some malicious code via injecting some JS as part of those...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Versions of Mattermost such as 11.5.1 and earlier 11.5.x series, 10.11.13 and earlier 10.11.x series, and 11.4.3 and earlier 11.4.x series have security vulnerabilities. These vulnerabilities stem fr...

Mattermost 代码问题漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Versions of Mattermost such as 11.5.1 and earlier 11.5.x series as well as 10.11.13 and earlier 10.11.x series have code vulnerabilities. These vulnerabilities stem from the lack of validation of the...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Versions of Mattermost such as 11.5.1 and earlier 11.5.x series, 10.11.13 and earlier 10.11.x series, and 11.4.3 and earlier 11.4.x series have security vulnerabilities. These vulnerabilities stem fr...

Mattermost Server 10.11.x < 10.11.13 Improper Validation (MMSA-2026-00603)

The version of Mattermost Server installed on the remote host is affected by a vulnerability as referenced in the MMSA-2026-00603 advisory. - Mattermost versions 10.11.x prior to 10.11.13 fail to validate whether users were correctly owned by the correct Connected Workspace which allows a malicio...

SUSE CVE-2026-26233

Mattermost versions 11.4.x = 11.4.0, 11.3.x = 11.3.1, 11.2.x = 11.2.3, 10.11.x = 10.11.11 fail to rate limit login requests which allows unauthenticated remote attackers to cause denial of service server crash and restart via HTTP/2 single packet attack with 100+ parallel login requests...

SUSE CVE-2026-2456

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 Mattermost fails to limit the size of responses from integration action endpoints, which allows an authenticated attacker to cause server memory exhaustion and denial of service via a malicious integration server that return...

SUSE CVE-2026-24692

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly enforce read permissions in search API endpoints which allows guest users without read permissions to access posts and files in channels via search API requests. Mattermost Advisory ID: MMSA-2025-00554...

SUSE CVE-2026-25783

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate User-Agent header tokens which allows an authenticated attacker to cause a request panic via a specially crafted User-Agent header. Mattermost Advisory ID: MMSA-2026-00586...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. There is a security vulnerability in Mattermost, which stems from an unvalidated target path for advanced log files. This vulnerability could allow system administrators to read arbitrary host files...

EUVD-2026-15806

Mattermost versions 11.2.x = 11.2.2, 10.11.x = 10.11.10, 11.4.x = 11.4.0, 11.3.x = 11.3.1 fail to properly validate CSRF tokens in the /api/v4/accesscontrolpolicies/policyid/activate endpoint, which allows an attacker to trick an admin into changing access control policy active status via a craft...

CVE-2026-26230 Team Admin Privilege Escalation to Demote Members to Guest

Mattermost versions 10.11.x = 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531...

Mattermost fails to validate user's authentication method when processing account auth type switch

Mattermost versions 10.11.x = 10.11.10 fail to validate user's authentication method when processing account auth type switch which allows an authenticated attacker to change account password without confirmation via falsely claiming a different auth provider.. Mattermost Advisory ID:...

GHSA-M5RV-56XX-HFC6 Mattermost fails to properly handle very long passwords

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly handle very long passwords, which allows an attacker to overload the server CPU and memory via executing login attempts with multi-megabyte passwords. Mattermost Advisory ID: MMSA-2026-00587...

CVE-2026-22545

Mattermost versions 10.11.x = 10.11.10 fail to validate user's authentication method when processing account auth type switch which allows an authenticated attacker to change account password without confirmation via falsely claiming a different auth provider.. Mattermost Advisory ID:...

CVE-2026-24458 DoS attack via login attempts with multi-megabyte passwords

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly handle very long passwords, which allows an attacker to overload the server CPU and memory via executing login attempts with multi-megabyte passwords. Mattermost Advisory ID: MMSA-2026-00587...

CVE-2026-26246

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to bound memory allocation when processing PSD image files which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted PSD file. Mattermost Advisory I...