Mattermost Fails to Validate Remote Cluster Upload Sessions

Mattermost versions 10.8.x = 10.8.3, 10.5.x = 10.5.8, 9.11.x = 9.11.17, 10.9.x = 10.9.2, 10.10.x = 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in...

CVE-2025-49222

Mattermost versions 10.8.x = 10.8.3, 10.5.x = 10.5.8, 9.11.x = 9.11.17, 10.9.x = 10.9.2, 10.10.x = 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in...

CVE-2025-49222 Mattermost Shared Channel Upload Type Validation Bypass

Mattermost versions 10.8.x = 10.8.3, 10.5.x = 10.5.8, 9.11.x = 9.11.17, 10.9.x = 10.9.2, 10.10.x = 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in...

CVE-2025-49222 Mattermost Shared Channel Upload Type Validation Bypass

Mattermost versions 10.8.x = 10.8.3, 10.5.x = 10.5.8, 9.11.x = 9.11.17, 10.9.x = 10.9.2, 10.10.x = 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in...

CVE-2024-39839

Mattermost versions 9.9.x = 9.9.0, 9.5.x = 9.5.6, 9.7.x = 9.7.5, 9.8.x = 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the...

CVE-2024-32939

Mattermost versions 9.9.x = 9.9.1, 9.5.x = 9.5.7, 9.10.x = 9.10.0, 9.8.x = 9.8.2, when shared channels are enabled, fail to redact remote users' original email addresses stored in user props when email addresses are otherwise configured not to be visible in the local server."...

BIT-MATTERMOST-2024-39837

Mattermost versions 9.9.x = 9.9.0, 9.5.x = 9.5.6 fail to properly restrict channel creation which allows a malicious remote to create arbitrary channels, when shared channels were enabled...

BIT-MATTERMOST-2024-39839

Mattermost versions 9.9.x = 9.9.0, 9.5.x = 9.5.6, 9.7.x = 9.7.5, 9.8.x = 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the...

BIT-MATTERMOST-2024-41144

Mattermost versions 9.9.x = 9.9.0, 9.5.x = 9.5.6, 9.7.x = 9.7.5, 9.8.x = 9.8.1 fail to properly validate synced posts, when shared channels are enabled, which allows a malicious remote to create/update/delete arbitrary posts in arbitrary channels...

BIT-MATTERMOST-2024-41162

Mattermost versions 9.9.x = 9.9.0, 9.5.x = 9.5.6, 9.7.x = 9.7.5 and 9.8.x = 9.8.1 fail to disallow the modification of local channels by a remote, when shared channels are enabled, which allows a malicious remote to make an arbitrary local channel read-only...

Mattermost doesn't redact remote users' original email addresses

Mattermost versions 9.9.x = 9.9.1, 9.5.x = 9.5.7, 9.10.x = 9.10.0, 9.8.x = 9.8.2, when shared channels are enabled, fail to redact remote users' original email addresses stored in user props when email addresses are otherwise configured not to be visible in the local server...

GHSA-C6VP-JJGV-38WJ Mattermost allows remote/synthetic users to create sessions, reset passwords

Mattermost versions 9.9.x = 9.9.1, 9.5.x = 9.5.7, 9.10.x = 9.10.0 and 9.8.x = 9.8.2 fail to ensure that remote/synthetic users cannot create sessions or reset passwords, which allows the munged email addresses, created by shared channels, to be used to receive email notifications and to reset...

CVE-2024-32939 Email addresses of remote users visible in props regardless of server settings

Mattermost versions 9.9.x = 9.9.1, 9.5.x = 9.5.7, 9.10.x = 9.10.0, 9.8.x = 9.8.2, when shared channels are enabled, fail to redact remote users' original email addresses stored in user props when email addresses are otherwise configured not to be visible in the local server."...

CVE-2024-32939

Mattermost CVE-2024-32939 affects multiple 9.x branches (9.9.x up to 9.9.1; 9.5.x up to 9.5.7; 9.10.x up to 9.10.0; 9.8.x up to 9.8.2) when shared channels are enabled. The issue is that remote users’ original email addresses stored in user props are not redacted even when emails are configured n...

CVE-2024-39836 Munged email address used for password resets and notifications

Mattermost versions 9.9.x = 9.9.1, 9.5.x = 9.5.7, 9.10.x = 9.10.0 and 9.8.x = 9.8.2 fail to ensure that remote/synthetic users cannot create sessions or reset passwords, which allows the munged email addresses, created by shared channels, to be used to receive email notifications and to reset...

CVE-2024-39836

Mattermost server vulnerable versions: 9.9.x <= 9.9.1, 9.5.x <= 9.5.7, 9.10.x <= 9.10.0, and 9.8.x

CVE-2024-32939: Improper Access Control

Mattermost versions 9.9.x = 9.9.1, 9.5.x = 9.5.7, 9.10.x = 9.10.0, 9.8.x = 9.8.2, when shared channels are enabled, fail to redact remote users' original email addresses stored in user props when email addresses are otherwise configured not to be visible in the local server."...

PT-2024-24990 · Mattermost · Mattermost

Name of the Vulnerable Software and Affected Versions: Mattermost versions 9.8.x through 9.8.2 Mattermost versions 9.5.x through 9.5.7 Mattermost versions 9.9.x through 9.9.1 Mattermost versions 9.10.x through 9.10.0 Description: The issue arises when shared channels are enabled in Mattermost,...

Improper Access Control

github.com/mattermost/mattermost-server is vulnerable to Improper Access Control. The vulnerability is caused due to a failure to disallow the modification of local channels by a remote, when shared channels are enabled. This allows a malicious remote user to make an arbitrary local channel...

Improper Access Control

github.com/mattermost/mattermost-server is vulnerable to Improper Access Control. The vulnerability is caused due to a failure to disallow users to set their own remote username when shared channels are enabled. This allows a user on a remote to set their remote username prop to an arbitrary...