Improper Validation of Specified Type of Input

Overview Affected versions of this package are vulnerable to Improper Validation of Specified Type of Input in the calls plugin when handling websocket messages containing malformed msgpack frames. An attacker can cause the server to consume excessive memory and crash by sending specially crafted...

CVE-2026-2454 DoS in Calls plugin via malformed msgpack in websocket request.

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to handle incorrectly reported array lengths which allows malicious user to cause OOM errors and crash the server via sending corrupted msgpack frames within websocket messages to calls plugin. Mattermost Advisory ID:...