CVE-2026-16044
Low
No strong exploitation signal.
CVSS base
5.4
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
EPSS — probability of exploitation (30 days)
0.2%
6.7th percentile
CISA KEV
Not listed
Weakness / dates
CWE-863
Published 2026-08-17 · modified 2026-08-18
CVSS breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
| Attack Vector | N | Network |
| Attack Complexity | L | Low |
| Privileges Required | L | Low |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | N | None |
| Integrity | L | Low |
| Availability | L | Low |
Timeline
- 2026-08-17 — Published (NVD)
- 2026-08-18 — Last modified (NVD)
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