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Vulnerability record · CVE-2026-16044 · published 17 August 2026

CVE-2026-16044: Mattermost server incorrect authorization vulnerability

Mattermost · Mattermost Server

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

5.4 CVSS 3.1 Medium EPSS 0.29% · top 80.9% CWE-863 · Incorrect authorization
5.4CVSS 3.1 base score
0.29%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References
18 Aug 2026Last modified by 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

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://mattermost.com/security-updates Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-16044), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.