CVE-2026-9693

EUVD-2026-60542
Mattermost versions 10.11.x <= 10.11.20, 11.7.x <= 11.7.5 Mattermost fails to remove thread membership records when a user is removed from or leaves a team, which allows a previously removed user who is later re-invited to the team to view private channel thread root post content and metadata via the team threads API.. Mattermost Advisory ID: MMSA-2026-00682
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
MattermostCNA
3.5 LOW
NETWORK
LOW
LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 17.55%
Affected Products (NVD)
VendorProductVersion
mattermostmattermost_server
10.11.0 ≤
𝑥
< 10.11.21
mattermostmattermost_server
11.7.0 ≤
𝑥
< 11.7.6
𝑥
= Vulnerable software versions
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.20
CNA
mattermostmattermost
11.7.0 ≤
𝑥
≤ 11.7.5
CNA
Common Weakness Enumeration
References
https://mattermost.com/security-updates