CVE-2026-91181

EUVD-2026-78160
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 Fail to sanitize Team objects returned by the data retention teams endpoint which allows an authenticated user holding only the read-only Data Retention Policy permission to obtain a private team's secret invite_id and email, and use it to join the team without authorization, via GET /api/v4/data_retention/policies/{policy_id}/teams.. Mattermost Advisory ID: MMSA-2026-00702
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
MattermostCNA
6.5 MEDIUM
NETWORK
LOW
HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 32.73%
Affected Products (NVD)
VendorProductVersion
mattermostmattermost_server
10.11.0 ≤
𝑥
< 10.11.23
mattermostmattermost_server
11.7.0 ≤
𝑥
< 11.7.8
mattermostmattermost_server
11.8.0 ≤
𝑥
< 11.8.5
mattermostmattermost_server
11.9.0 ≤
𝑥
< 11.9.1
𝑥
= Vulnerable software versions
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources (CNA/ADP records, vendor advisories, Enginsight analysis).
VendorProductVersionSource
mattermostmattermost
11.9.0
CNA
mattermostmattermost
11.8.0 ≤
𝑥
≤ 11.8.4
CNA
mattermostmattermost
11.7.0 ≤
𝑥
≤ 11.7.7
CNA
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.22
CNA