Exposure of Sensitive Information Through Metadata

Overview github.com/mattermost/mattermost/server/channels/app is a private-cloud Slack alternative Affected versions of this package are vulnerable to Exposure of Sensitive Information Through Metadata when executing the UpdateChannelBookmark function, due to improper handling of user permissions...

GO-2025-3604 Mattermost Fails to Enforce Proper Access Controls on `/api/v4/audits` Endpoint in github.com/mattermost/mattermost-server

Mattermost Fails to Enforce Proper Access Controls on /api/v4/audits Endpoint in github.com/mattermost/mattermost-server...

Improper Access Control

github.com/mattermost/mattermost-server is vulnerable to Improper Access Control. The vulnerability is due to insufficient enforcement of access restrictions on the /api/v4/audits endpoint, allowing users with delegated granular administration roles to access User Activity Logs without Compliance...

CVE-2025-27936

CVE-2025-27936 (Mattermost/MS Teams plugin timing attack) : The connected advisory GO-2025-3618 reports a vulnerability in the Mattermost ecosystem where the MSTeams plugin (github.com/mattermost/mattermost-plugin-msteams) and related Mattermost Server versions are susceptible to an observable ti...

CVE-2025-27936 Webhook Secret Exposure via Timing attack in MSteams plugin

Mattermost Plugin MSTeams versions 2.1.0 and Mattermost Server versions 10.5.x =10.5.1 with the MS Teams plugin enabled fail to perform constant time comparison on a MSTeams plugin webhook secret which allows an attacker to retrieve the webhook secret of the MSTeams plugin via a timing attack...

PT-2025-16571 · Mattermost · Mattermost Server +1

Name of the Vulnerable Software and Affected Versions: Mattermost Plugin MSTeams versions prior to 2.1.0 Mattermost Server versions 10.5.x through 10.5.1 Description: The issue allows an attacker to retrieve the webhook secret of the MSTeams plugin via a timing attack during webhook secret...

Incorrect Authorization

Overview Affected versions of this package are vulnerable to Incorrect Authorization in that a user with the "Edit Other Users" permission set, but not broader high-level permissions, can modify the properties of admin accounts. Remediation Upgrade...

Mattermost Server 9.11.x < 9.11.9 / 10.3.x < 10.3.4 / 10.4.x < 10.4.3 (MMSA-2025-00421)

The version of Mattermost Server installed on the remote host is prior to 9.11.9, 10.3.4, or 10.4.3. It is, therefore, affected by a vulnerability as referenced in the MMSA-2025-00421 advisory. - Mattermost versions 10.4.x = 10.4.2, 10.3.x = 10.3.3, 9.11.x = 9.11.8 fail to restrict command...

Mattermost Server 9.11.x < 9.11.9 (MMSA-2024-00409)

The version of Mattermost Server installed on the remote host is prior to 9.11.9. It is, therefore, affected by a vulnerability as referenced in the MMSA-2024-00409 advisory. - Mattermost versions 9.11.x = 9.11.8 fail to prompt for explicit approval before adding a team admin to a private channel...

Mattermost Server 9.11.x < 9.11.9 / 10.3.x < 10.3.4 / 10.4.x < 10.4.3 (MMSA-2025-00418)

The version of Mattermost Server installed on the remote host is prior to 9.11.9, 10.3.4, or 10.4.3. It is, therefore, affected by a vulnerability as referenced in the MMSA-2025-00418 advisory. - Mattermost versions 10.4.x = 10.4.2, 10.3.x = 10.3.3, 9.11.x = 9.11.8 fail to fail to enforce channel...

Mattermost Server 9.11.x < 9.11.9 / 10.3.x < 10.3.4 / 10.4.x < 10.4.3 (MMSA-2025-00422)

The version of Mattermost Server installed on the remote host is prior to 9.11.9, 10.3.4, or 10.4.3. It is, therefore, affected by a vulnerability as referenced in the MMSA-2025-00422 advisory. - Mattermost versions 10.4.x = 10.4.2, 10.3.x = 10.3.3, 9.11.x = 9.11.8 fail to enforce MFA on certain...

Mattermost Server 9.11.x < 9.11.9 / 10.3.x < 10.3.4 / 10.4.x < 10.4.3 / 10.5 (MMSA-2025-00444)

The version of Mattermost Server installed on the remote host is prior to 9.11.9, 10.3.4, 10.4.3, or 10.5. It is, therefore, affected by a vulnerability as referenced in the MMSA-2025-00444 advisory. - Mattermost versions 10.4.x = 10.4.2, 10.3.x = 10.3.3, 9.11.x = 9.11.8, 10.5.x = 10.5.0 fail to...

Mattermost Server 10.4.x < 10.4.3 / 10.3.x < 10.3.4 /9.11.x < 9.11.9 / 10.5.x < 10.5.1 (MMSA-2025-00432)

The version of Mattermost Server installed on the remote host is prior to 10.4.4 / 10.3.4 / 9.11.9 / 10.5.1. It is, therefore, affected by a vulnerability as referenced in the MMSA-2025-00432 advisory. - Mattermost versions 10.4.x = 10.4.2, 10.3.x = 10.3.3, 9.11.x = 9.11.8, 10.5.x = 10.5.0 fail t...

Incorrect Authorization

Overview Affected versions of this package are vulnerable to Incorrect Authorization due to improper enforcement of channel conversion restrictions. An attacker can exploit this flaw to change channel visibility settings without proper authorization by manipulating channel settings. Remediation...

Incorrect Authorization

Overview Affected versions of this package are vulnerable to Incorrect Authorization when an admin user adds itself to a private channel by clicking a permalink. Remediation Upgrade github.com/mattermost/mattermost/server/channels/api4 to version 9.11.9-rc1 or higher. References - GitHub Commit...

Missing Authentication for Critical Function

Overview Affected versions of this package are vulnerable to Missing Authentication for Critical Function due to servePluginRequest failing to enforce multifactor authentication for plugins, even when MFA is meant to be enabled. Remediation Upgrade...

Unauthorized Channel Content Export

github.com/mattermost/mattermost-server is vulnerable to unauthorized channel content export. The vulnerability is due to improper access control due to failing to restrict channel export of archived channels when the "Allow users to view archived channels" setting is disabled...

Arbitrary File Read

github.com/mattermost/mattermost-server is vulnerable to Arbitrary File Read. The vulnerability is due to improper validation of board blocks when importing boards, which allows an attacker to perform a path traversal attack by importing and exporting a specially crafted import archive in Boards...

Session Fixation

github.com/mattermost/mattermost-server is vulnerable to Session Fixation. The vulnerability is due to improper session invalidation when converting a user to a bot, allows the user to retain their previous session and potentially escalate privileges based on the bot’s assigned permissions...

Mattermost Server 9.11.x < 9.11.7 / 10.4.x < 10.4.2 (MMSA-2025-00414)

The version of Mattermost Server installed on the remote host is prior to 9.11.7 or 10.4.2. It is, therefore, affected by a vulnerability as referenced in the MMSA-2025-00414 advisory. - Mattermost versions 9.11.x = 9.11.6, 10.4.x = 10.4.1 fail to invalidate all active sessions when converting a...