CVE-2026-4635
MEDIUM
mattermost
mattermost_server
NVD
CVSS Score
6.5
Severity
MEDIUM
Published
May 22, 2026
Vendor
mattermost
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 archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message between the server deleting existing persistent notifications and archiving the channel.. Mattermost Advisory ID: MMSA-2026-00637