CVE-2026-16044CWE-863broken-access-control

CVE-2026-16044

Medium · published August 17, 2026

CVSS v3.1
5.4
EPSS
0%
Percentile
20.1
In the wild
Unconfirmed
What it is

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

The record
Technical detail
CVSS v3.1
5.4 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
CVSS v4.0
Not supplied
EPSS
0.00287 · 20.1th percentile
Weakness
CWE-863 · Incorrect Authorization
Published
2026-08-17T19:16Z
Affected products (2)
ProductVersionsFixed in
mattermost/mattermost_server≥ 10.11.0, < 10.11.2210.11.22
mattermost/mattermost_server≥ 11.7.0, < 11.7.711.7.7
References (1)
https://mattermost.com/security-updates · [email protected]
EPSS history
Timeline
  • 17 AUG 14:26Z
    Insufficient validation of guest board admin privileges on archive import
    cvelistv5