CVE-2026-5740 | BDVDB-2026-334474 Detail
MattermostMattermost
Description#
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to properly validate msgpack-encoded WebSocket frames before memory allocation which allows an unauthenticated remote attacker to crash the server process and cause a full service outage for all users via a crafted binary WebSocket message sent to the public WebSocket endpoint.. Mattermost Advisory ID: MMSA-2026-00647
Impact#
Per CVSS v3.1: confidentiality impact none, integrity impact none, availability impact high. Attack vector: network.
Weaknesses#
- CWE-789 Memory Allocation with Excessive Size Value
References#
Exploit#
No public exploit known
History#
- Version 1Record published in the CVE List.