CVE-2026-15754
MEDIUM
4,2
Source: [email protected]
Attack Vector: network
Attack Complexity: high
Privileges Required: high
User Interaction: required
Scope: unchanged
Confidentiality: none
Integrity: high
Availability: none
Description
AI Translation Available
Mattermost versions 11.7.x <= 11.7.6, 11.8.x <= 11.8.3 The access control policy unassign endpoint fails to re-validate that each target channel still belongs to the requesting admin's team, which allows an authenticated team administrator to remove ABAC (attribute-based access control) policy assignments from channels outside their team via the policy unassign API after a channel has been moved to another team.. Mattermost Advisory ID: MMSA-2026-00718
863
Incorrect 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
Execute Unauthorized Code Or Commands
Dos: Crash, Exit, Or Restart
Dos: Resource Consumption (Cpu)
Dos: Resource Consumption (Memory)
Dos: Resource Consumption (Other)
Applicable Platforms
Technologies:
Web Server, Database Server, Not Technology-Specific
https://mattermost.com/security-updates