CVE-2026-8823 | Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fa… | CVSS 3.8 LOW

Description

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

Metadata

CVE ID: CVE-2026-8823
State: PUBLISHED
Assigner: Mattermost
Reserved: 2026-05-18 10:05 UTC
Published: 2026-06-22 13:41 UTC
Last updated: 2026-06-22 16:12 UTC
Primary CWE: CWE-863
CWE-863: Incorrect Authorization
Vendor / Product: Mattermost / Mattermost
Sources: cve.org · NVD

Severity & Metrics

3.8 LOW CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
Mattermost	Mattermost	—	11.7.0 ≤ 11.7.0, 10.11.0 ≤ 10.11.17, 11.8.0, 11.7.1 …

Weakness (CWE)

CWE	Source	Description
CWE-863	cna	CWE-863: Incorrect Authorization

CVSS scores (1)

Score	Severity	Version	Source	Vector
3.8	LOW	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L

References (1)

MMSA-2026-00669 https://mattermost.com/security-updates