CVE-2026-3115

EUVD-2026-16245
Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
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
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
Affected Products (NVD)
VendorProductVersion
mattermostmattermost
11.2.0 ≤
𝑥
≤ 11.2.2
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.10
mattermostmattermost
𝑥
≤ 11.4.0
mattermostmattermost
11.3.0 ≤
𝑥
≤ 11.3.1
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://mattermost.com/security-updates