CVE-2026-3433

EUVD-2026-36498
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to restrict role_updated websocket event broadcasts to members of the affected team or channel which allows an authenticated attacker with guest-level access to observe permission scheme change notifications for private teams they are not a member of via the websocket connection.. Mattermost Advisory ID: MMSA-2026-00616
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
MattermostCNA
4.3 MEDIUM
NETWORK
LOW
LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mattermostmattermost
11.6.0 ≤
𝑥
≤ 11.6.1
CNA
mattermostmattermost
11.5.0 ≤
𝑥
≤ 11.5.4
CNA
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.15
CNA
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.16
CNA
Common Weakness Enumeration
References
https://mattermost.com/security-updates