4.3
MEDIUM CVSS 3.1
CVE-2026-14259
Board archive import bypasses team board creation permissions
Description

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to enforce board creation permissions when importing archive files which allows an authenticated non-guest team member to create Open or Private boards despite administrator restrictions via importing a crafted .boardarchive file. Mattermost Advisory ID: MMSA-2026-00712

INFO

Published Date :

Sept. 14, 2026, 10:26 a.m.

Last Modified :

Sept. 14, 2026, 10:26 a.m.

Remotely Exploit :

Yes !

Source :

Mattermost
Affected Products

The following products are affected by CVE-2026-14259 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM 9302f53e-dde5-4bf3-b2f2-a83f91ac0eee
Solution
Update Mattermost to a version that enforces board creation permissions to prevent unauthorized board creation.
  • Update Mattermost to version 11.9.1 or later.
  • Update Mattermost to version 11.8.5 or later.
  • Update Mattermost to version 11.7.8 or later.
  • Apply security updates for your Mattermost instance.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-14259 vulnerability anywhere in the article.

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.