CVE-2026-8823

EUVD-2026-38276
Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
MattermostCNA
3.8 LOW
NETWORK
LOW
HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L
Base Score
CVSS 3.x
EPSS Score
Percentile: 24.17%
Affected Products (NVD)
VendorProductVersion
mattermostmattermost_server
10.11.0 ≤
𝑥
< 10.11.18
mattermostmattermost_server
11.7.0 ≤
𝑥
< 11.7.1
𝑥
= Vulnerable software versions
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mattermostmattermost
𝑥
≤ 11.7.0
CNA
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.17
CNA
Common Weakness Enumeration
References
https://mattermost.com/security-updates