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Fencer Vulns
medium 4.3

CVE-2026-14259 json

Board archive import bypasses team board creation permissions

published 2026-09-14 56 d ago modified 2026-10-07 32 d ago also EUVD-2026-77359

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

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

Patch / fix

  • Mattermost Mattermost 10.11.23, 11.7.8, 11.8.5, 11.9.1, 11.10.0

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
55 d ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected products

  • Mattermost Mattermost

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.