Unauthorized Subscription Edit to Confluence Space in Mattermost Confluence Plugin

Vulnerability

Description

The Mattermost Confluence Plugin versions prior to 1.5.0 fail to verify whether a user has the necessary access rights to a Confluence space when processing subscription edit requests. This authorization bypass occurs in the edit subscription endpoint, which does not validate the user's permissions against the target Confluence space [1].

Exploitation

An attacker who is an authenticated Mattermost user with access to the plugin's subscription management functionality can exploit this flaw. By sending a crafted request to the edit subscription endpoint, the attacker can modify subscriptions for any Confluence space, regardless of their actual access permissions. No special network position or additional privileges are required beyond standard Mattermost access [1][2].

Impact

Successful exploitation allows an attacker to alter subscription configurations for Confluence spaces they should not have access to. This could lead to unauthorized notifications being sent to Mattermost channels, modification of subscription aliases, or other changes that affect how Confluence events are relayed to users [2].

Mitigation

The vulnerability is fixed in Mattermost Confluence Plugin version 1.5.0. Users should upgrade to this version or later to prevent unauthorized subscription edits [1].