4.3 MEDIUM
- CVSS version (CVSS): 3.1
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): Low (L)
- Privileges Required (PR): Low (L)
- User Interaction (UI): None (N)
- Scope (S): Unchanged (U)
- Confidentiality (C): None (N)
- Integrity (I): Low (L)
- Availability (A): None (N)
- Modified Attack Vector (MAV): Network (N)
- Modified Attack Complexity (MAC): Low (L)
- Modified Privileges Required (MPR): Low (L)
- Modified User Interaction (MUI): None (N)
- Modified Confidentiality (MC): None (N)
- Modified Scope (MS): Unchanged (U)
- Modified Integrity (MI): Low (L)
- Modified Availability (MA): None (N)
Activity log
- Created suggestion
Insufficient authorization in shared channel membership sync allows remote cluster to remove users from arbitrary channels
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate that a remote cluster has access to a channel before processing membership removal requests during shared channel membership sync, which allows a malicious remote cluster to remove any user from any channel, including private channels, via crafted membership sync messages targeting channels the remote cluster is not authorized to access. Mattermost Advisory ID: MMSA-2026-00576
References
-
MMSA-2026-00576 vendor-advisory
Affected products
- ==11.6.0
- =<11.4.3
- ==10.11.14
- =<10.11.13
- ==11.4.4
- =<11.5.1
- ==11.5.2
Matching in nixpkgs
pkgs.mattermost
Open source platform for secure collaboration across the entire software development lifecycle
pkgs.mattermostLatest
Open source platform for secure collaboration across the entire software development lifecycle
pkgs.mattermost-desktop
Mattermost Desktop client
pkgs.python312Packages.mattermostdriver
Python Mattermost Driver
pkgs.python313Packages.mattermostdriver
Python Mattermost Driver
pkgs.python314Packages.mattermostdriver
Python Mattermost Driver
Package maintainers
-
@numinit Morgan Jones <me+nixpkgs@numin.it>
-
@Kranzes Ilan Joselevich <personal@ilanjoselevich.com>
-
@mgdelacroix Miguel de la Cruz <mgdelacroix@gmail.com>
-
@ryantm Ryan Mulligan <ryan@ryantm.com>
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@jokogr Ioannis Koutras <ioannis.koutras@gmail.com>
-
@yayayayaka Yaya <github@uwu.is>
-
@liff Olli Helenius <liff@iki.fi>
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@globin Robin Gloster <mail@glob.in>