Unexpected Input to Cloud Webhook endpoint Causes DoS in Mattermost Confluence Plugin

Vulnerability

CVE-2025-54463 describes a denial-of-service vulnerability in the Mattermost Confluence Plugin (versions before 1.5.0). The plugin fails to properly handle unexpected or malformed request bodies. When the server webhook endpoint receives a request with an invalid body, the plugin does not gracefully handle the exception, allowing an attacker to crash the plugin process [1][3].

Exploitation

An attacker can exploit this vulnerability by sending a continuous stream of crafted requests to the Confluence plugin's webhook endpoint. No authentication is mentioned as a prerequisite for the webhook, suggesting the endpoint may be publicly accessible or reachable from within the network. The only requirement is network access to the endpoint [1].

Impact

The primary impact is a denial of service. By repeatedly crashing the plugin, the attacker prevents the Confluence integration from functioning, meaning no Confluence events (page updates, comments, etc.) are received in Mattermost channels. This can disrupt team collaboration workflows that depend on real-time Confluence notifications [1][2].

Mitigation

The vulnerability is fixed in version 1.5.0 of the Mattermost Confluence Plugin. Administrators should upgrade to the latest version as soon as possible. Mattermost publishes security updates on their official security page [4]. No other workarounds are documented in the available references.