PT-2026-76875

Name of the Vulnerable Software and Affected Versions Mattermost versions 10.11.0 through 10.11.20 Mattermost versions 11.7.0 through 11.7.5 Description The software fails to remove thread membership records when a user leaves or is removed from a team. This allows a user who is subsequently...

CVE-2026-48076: Incorrect Authorization

OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. The new-client booking flow in versions 1.0.1 and prior consists of three calls: bootstrap-challenge returns a 16-bit PoW challenge with difficulty=4 leading hex zeroes, bootstrap-verify...

PT-2026-57655

Mattermost versions 11.7.x = 11.7.2, 11.6.x = 11.6.4, 10.11.x = 10.11.19 fail to verify that the channel referenced in an action cookie matches the channel of the target post, which allows an authenticated user without access to a private channel to trigger interactive post actions on posts in th...

CVE-2026-5163 Missing authorization check in AI message rewrite endpoint allows access to private thread content

Mattermost versions 11.5.x = 11.5.1 fail to verify channel membership when processing AI-assisted message rewrites which allows an authenticated attacker to read the content of threads in private channels and direct messages they do not have access to via a crafted request to the post rewrite...

EUVD-2026-12516

Mattermost versions 10.11.x = 10.11.10 Fail to invalidate cached permalink preview data when a user loses channel access which allows the user to continue viewing private channel content via previously cached permalink previews until cache reset or relogin.. Mattermost Advisory ID: MMSA-2026-0058...

Mattermost has an Incorrect Authorization vulnerability

Mattermost versions 10.5.x = 10.5.10, 10.11.x = 10.11.2 fail to properly validate guest user permissions when adding channel members which allows guest users to add any team members to their private channels via the /api/v4/channels/channelid/members endpoint...

EUVD-2023-32055

Malicious code in bioql PyPI...

EUVD-2023-0969

Malicious code in bioql PyPI...

GHSA-7H34-9CHR-58QH Mattermost Missing Authentication for Critical Function

Mattermost versions 10.5.x = 10.5.6, 10.8.x = 10.8.1, 10.7.x = 10.7.3, 9.11.x = 9.11.16 fail to verify authorization when retrieving cached posts by PendingPostID which allows an authenticated user to read posts in private channels they don't have access to via guessing the PendingPostID of...

Missing Authentication for Critical Function

Overview github.com/mattermost/mattermost/server/channels/app is a private-cloud Slack alternative Affected versions of this package are vulnerable to Missing Authentication for Critical Function in the deduplicateCreatePost method. An attacker can access posts in private channels without proper...

CVE-2025-6226

Mattermost versions 10.5.x = 10.5.6, 10.8.x = 10.8.1, 10.7.x = 10.7.3, 9.11.x = 9.11.16 fail to verify authorization when retrieving cached posts by PendingPostID which allows an authenticated user to read posts in private channels they don't have access to via guessing the PendingPostID of...

CVE-2025-6226 IDOR in CreatePost API allows for timeboxed message disclosure

Mattermost versions 10.5.x = 10.5.6, 10.8.x = 10.8.1, 10.7.x = 10.7.3, 9.11.x = 9.11.16 fail to verify authorization when retrieving cached posts by PendingPostID which allows an authenticated user to read posts in private channels they don't have access to via guessing the PendingPostID of...

CVE-2025-47871

Mattermost versions 10.5.x = 10.5.5, 9.11.x = 9.11.15, 10.8.x = 10.8.0, 10.7.x = 10.7.2, 10.6.x = 10.6.5 fail to properly validate channel membership when retrieving playbook run metadata, allowing authenticated users who are playbook members but not channel members to access sensitive informatio...

Mattermost Incorrect Authorization vulnerability

Mattermost versions 10.5.x = 10.5.5, 9.11.x = 9.11.15, 10.8.x = 10.8.0, 10.7.x = 10.7.2, 10.6.x = 10.6.5 fail to properly validate channel membership when retrieving playbook run metadata, allowing authenticated users who are playbook members but not channel members to access sensitive informatio...

CVE-2025-47871 Mattermost Playbooks exposes private channel metadata to unauthorized users via run metadata API

Mattermost versions 10.5.x = 10.5.5, 9.11.x = 9.11.15, 10.8.x = 10.8.0, 10.7.x = 10.7.2, 10.6.x = 10.6.5 fail to properly validate channel membership when retrieving playbook run metadata, allowing authenticated users who are playbook members but not channel members to access sensitive informatio...

CVE-2023-1774

When processing an email invite to a private channel on a team, Mattermost fails to validate the inviter's permission to that channel, allowing an attacker to invite themselves to a private channel...

BIT-MATTERMOST-2025-27715

Mattermost versions 9.11.x = 9.11.8 fail to prompt for explicit approval before adding a team admin to a private channel, which team admins to joining private channels via crafted permalink links without explicit consent from them...

GO-2025-3555 Mattermost fail to prompt for explicit approval before adding a team admin to a private channel in github.com/mattermost/mattermost-server

Mattermost fail to prompt for explicit approval before adding a team admin to a private channel in github.com/mattermost/mattermost-server...

GHSA-CW7Q-5CGC-H3H9 Mattermost fail to prompt for explicit approval before adding a team admin to a private channel

Mattermost versions 9.11.x = 9.11.8 fail to prompt for explicit approval before adding a team admin to a private channel, which team admins to joining private channels via crafted permalink links without explicit consent from them...

Mattermost fail to prompt for explicit approval before adding a team admin to a private channel

Mattermost versions 9.11.x = 9.11.8 fail to prompt for explicit approval before adding a team admin to a private channel, which team admins to joining private channels via crafted permalink links without explicit consent from them...