CVE-2026-14259

MEDIUMCVSS 4.3/10EPSS 0.15%

Last modified

CVE-2026-14259 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. 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. EPSS estimates a 0.15% chance of exploitation in the next 30 days.

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

Metrics

EPSS Probability
0.15%

4.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
MattermostMattermost>= 11.9.0, <= 11.9.0; >= 11.8.0, <= 11.8.4; >= 11.7.0, <= 11.7.7; >= 10.11.0, <= 10.11.22

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-14259?
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
How severe is CVE-2026-14259?
CVE-2026-14259 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.15% probability of exploitation in the next 30 days.
How do I fix CVE-2026-14259?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST