CVE-2026-16044

Insufficient validation of guest board admin privileges on archive import

State: Published
Severity: 3.9 Low
Published: Aug 17, 2026
Updated: Aug 17, 2026
Reserved: Jul 17, 2026

Description

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID: MMSA-2026-00672

Scores

CVSS	Score	Vector	Source
3.1	3.9 Low	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L	Mattermost

Weaknesses

CWE-863 Incorrect Authorization

Affected Products

Product	Versions
MattermostMattermost	11.7.0 through 11.7.6Affected 10.11.0 through 10.11.21Affected 11.9.0Not affected 11.7.7Not affected 10.11.22Not affected

References

MMSA-2026-00672vendor-advisory

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