Medium (5.3) in mattermost mattermost. EPSS 0.3% chance of exploitation in the next 30 days.
Mattermost versions 9.5.x <= 9.5.5 and 9.8.0 fail to properly sanitize the recipients of a webhook event which allows an attacker monitoring webhook events to retrieve the channel IDs of archived or restored channels.
Severity
CVSS 3.1
5.3 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS
0.3% chance of exploitation in the next 30 days; higher than 28% of CVEs (scores of 2026-10-31)