CVE-2026-16047
MEDIUM
4,3
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: low
User Interaction: none
Scope: unchanged
Confidentiality: low
Integrity: none
Availability: none
Description
AI Translation Available
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fail to validate that users have read access to a channel before linking a board to it, which allows an authenticated attacker to discover the membership of private channels on the same team via creating, patching, importing, or bulk-creating boards with an arbitrary channelId. Mattermost Advisory ID: MMSA-2026-00674
862
Missing Authorization
IncompleteCommon Consequences
Security Scopes Affected:
Confidentiality
Integrity
Access Control
Availability
Potential Impacts:
Read Application Data
Read Files Or Directories
Modify Application Data
Modify Files Or Directories
Gain Privileges Or Assume Identity
Bypass Protection Mechanism
Dos: Crash, Exit, Or Restart
Dos: Resource Consumption (Cpu)
Dos: Resource Consumption (Memory)
Dos: Resource Consumption (Other)
Applicable Platforms
Technologies:
AI/ML, Web Server, Database Server, Not Technology-Specific
https://mattermost.com/security-updates