EUVD-2026-31425

Mattermost versions 11.6.x = 11.6.0, 11.5.x = 11.5.3, 11.4.x = 11.4.4, 10.11.x = 10.11.14 fail to enforce request body size limits on plugin HTTP endpoints which allows an attacker to cause a denial of service via crafted oversized HTTP requests.. Mattermost Advisory ID: MMSA-2026-00646...

CVE-2026-5308 Missing request body size limits on Zoom plugin HTTP endpoints

Mattermost versions 11.6.x = 11.6.0, 11.5.x = 11.5.3, 11.4.x = 11.4.4, 10.11.x = 10.11.14 fail to enforce request body size limits on plugin HTTP endpoints which allows an attacker to cause a denial of service via crafted oversized HTTP requests.. Mattermost Advisory ID: MMSA-2026-00646...

CVE-2026-5755

CVE-2026-5755 affects Mattermost releases 11.6.x up to 11.6.0, 11.5.x up to 11.5.2/11.5.3, 11.4.x up to 11.4.4, and 10.11.x up to 10.11.14. The issue arises from failure to validate the TIFF IFD offset in the image header before memory allocation, allowing authenticated users with file upload or ...

CVE-2026-5755

Mattermost versions 11.6.x = 11.6.0, 11.5.x = 11.5.2, 11.5.x = 11.5.3, 11.4.x = 11.4.4, 10.11.x = 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a denial of service serve...

CVE-2026-5755 Denial of service via crafted TIFF file upload

Mattermost versions 11.6.x = 11.6.0, 11.5.x = 11.5.2, 11.5.x = 11.5.3, 11.4.x = 11.4.4, 10.11.x = 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a denial of service serve...

CVE-2026-5755 Denial of service via crafted TIFF file upload

Mattermost versions 11.6.x = 11.6.0, 11.5.x = 11.5.2, 11.5.x = 11.5.3, 11.4.x = 11.4.4, 10.11.x = 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a denial of service serve...

CVE-2026-5755 Denial of service via crafted TIFF file upload

Mattermost versions 11.6.x = 11.6.0, 11.5.x = 11.5.2, 11.5.x = 11.5.3, 11.4.x = 11.4.4, 10.11.x = 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a denial of service serve...

PT-2026-42751

Name of the Vulnerable Software and Affected Versions Mattermost version 11.6.0 Mattermost version 11.5.3 Mattermost version 11.4.4 Mattermost version 10.11.14 Description Authenticated users with file upload or posting permissions can cause a denial of service resulting in server Out of Memory O...

PT-2026-42746

Name of the Vulnerable Software and Affected Versions Mattermost version 11.6.0 Mattermost version 11.5.3 Mattermost version 11.4.4 Mattermost version 10.11.14 Description Insufficient sanitization of team member data returned via API endpoints allows users without elevated permissions to obtain...

PT-2026-42749

Name of the Vulnerable Software and Affected Versions Mattermost version 11.6.0 Mattermost version 11.5.3 Mattermost version 11.4.4 Mattermost version 10.11.14 Description Failure to enforce request body size limits on plugin HTTP endpoints allows an attacker to cause a denial of service by sendi...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Vulnerabilities exist in versions of Mattermost 11.6.0 and earlier 11.6.x series, as well as versions prior to 11.5.3 11.5.x series, 11.4.4 and earlier 11.4.x series, and 10.11.14 and earlier 10.11.x...

Mattermost Server 11.4.x <= 11.4.3 / 11.5.x <= 11.5.1 Origin Validation Error (MMSA-2026-00636)

The version of Mattermost Server installed on the remote host is affected by a vulnerability as referenced in the MMSA-2026-00636 advisory. - Mattermost versions 11.5.x = 11.5.1, 11.4.x = 11.4.3 fail to validate the X-Requested-With header on the burn-on-read reveal endpoint which allows an...

PT-2026-42799

Name of the Vulnerable Software and Affected Versions Mattermost version 11.6.0 Mattermost version 11.5.3 Mattermost version 11.4.4 Mattermost version 10.11.14 Description An issue exists where the software fails to validate the OAuth token scope during the callback process. This allows an...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Vulnerabilities exist in versions of Mattermost 11.6.0 and earlier 11.6.x series, as well as versions prior to 11.5.3 11.5.x series, 11.4.4 and earlier 11.4.x series, and 10.11.14 and earlier 10.11.x...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Vulnerabilities exist in versions of Mattermost 11.6.0 and earlier 11.6.x series, as well as versions prior to 11.5.3 11.5.x series, 11.4.4 and earlier 11.4.x series, and 10.11.14 and earlier 10.11.x...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Vulnerabilities exist in versions of Mattermost 11.6.0 and earlier 11.6.x series, as well as versions prior to 11.5.3 11.5.x series, 11.4.4 and earlier 11.4.x series, and 10.11.14 and earlier 10.11.x...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Vulnerabilities exist in versions of Mattermost 11.6.0 and earlier 11.6.x series, as well as versions prior to 11.5.3 11.5.x series, 11.4.4 and earlier 11.4.x series, and 10.11.14 and earlier 10.11.x...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Vulnerabilities exist in versions of Mattermost 11.6.0 and earlier 11.6.x series, as well as versions prior to 11.5.3 11.5.x series, 11.4.4 and earlier 11.4.x series, and 10.11.14 and earlier 10.11.x...

PT-2026-42750

Name of the Vulnerable Software and Affected Versions Mattermost version 11.6.0 Mattermost version 11.5.3 Mattermost version 11.4.4 Mattermost version 10.11.14 Description An issue exists where msgpack-encoded WebSocket frames are not properly validated before memory allocation. This allows an...

PT-2026-42748

Name of the Vulnerable Software and Affected Versions Mattermost version 11.6.0 Mattermost version 11.5.3 Mattermost version 11.4.4 Mattermost version 10.11.14 Description Insufficient input validation in the GitHub plugin API request handlers allows an authenticated attacker to cause a denial of...