GO-2026-5769 Mattermost doesn't validate the X-Requested-With header on the burn-on-read reveal endpoint in github.com/mattermost/mattermost-server

Mattermost doesn't validate the X-Requested-With header on the burn-on-read reveal endpoint 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 causing...

CVE-2026-6339

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 authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost...

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...

Origin Validation Error

Overview Affected versions of this package are vulnerable to Origin Validation Error via the burn-on-read reveal endpoint due to missing validation of the X-Requested-With header. An attacker can force the unauthorized reveal of a burn-on-read message without recipient consent by sending a crafte...

Mattermost doesn't validate the X-Requested-With header on the burn-on-read reveal endpoint

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 authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost...

GHSA-XVCX-MGPC-5XH3 Mattermost doesn't validate the X-Requested-With header on the burn-on-read reveal endpoint

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 authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost...

CVE-2026-6339

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 authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost...

CVE-2026-6339

Mattermost contains a vulnerability (CVE-2026-6339) in versions 11.5.x &lt;= 11.5.1 and 11.4.x

CVE-2026-6339 Missing request origin validation on burn-on-read reveal endpoint

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 authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost...

CVE-2026-6339

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 authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost...

CVE-2026-6339 Missing request origin validation on burn-on-read reveal endpoint

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 authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost...

EUVD-2026-30749

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 authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost...

CVE-2026-6339 Missing request origin validation on burn-on-read reveal endpoint

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 authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost...

Mattermost 访问控制错误漏洞

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 11.4.3 and earlier 11.4.x series, have a access control vulnerability. This vulnerability stems from the failure to validat...

PT-2026-41657

Name of the Vulnerable Software and Affected Versions Mattermost versions 11.4.x through 11.4.3 Mattermost versions 11.5.x through 11.5.1 Description An issue exists where the burn-on-read reveal endpoint fails to validate the 'X-Requested-With' header. This allows an authenticated channel member...

SUSE CVE-2026-2578

Mattermost versions 11.3.x = 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event.. Mattermost Advisory ID: MMSA-2026-00579...

CVE-2026-2578

Mattermost versions 11.3.x = 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event.. Mattermost Advisory ID: MMSA-2026-00579...

GO-2026-4734 Mattermost fails to preserve the redacted state of burn-on-read posts during deletion in github.com/mattermost/mattermost-server

Mattermost fails to preserve the redacted state of burn-on-read posts during deletion 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 causing...

Mattermost fails to preserve the redacted state of burn-on-read posts during deletion

Mattermost versions 11.3.x = 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event. Mattermost Advisory ID: MMSA-2026-00579...

EUVD-2026-12415

Mattermost versions 11.3.x = 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event.. Mattermost Advisory ID: MMSA-2026-00579...