CVE-2026-14259Network attack vectorHinoki check available

Unauthorized board creation via crafted archive import

Published Sep 14, 2026 · Updated Sep 14, 2026

Incorrect authorization in Mattermost allows remote authenticated users to create administrator-restricted boards through archive import. The Boards archive import handler creates Open or Private boards from crafted .boardarchive content without enforcing configured team board-creation permissions. Affected releases are 10.11.0 through 10.11.22, 11.7.0 through 11.7.7, 11.8.0 through 11.8.4, and 11.9.0; non-guest team membership and archive-import access are required.

CVSS severityUnavailable
Unscored
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Incorrect authorization in Mattermost allows remote authenticated users to create administrator-restricted boards through archive import. The Boards archive import handler creates Open or Private boards from crafted .boardarchive content without enforcing configured team board-creation permissions. Affected releases are 10.11.0 through 10.11.22, 11.7.0 through 11.7.7, 11.8.0 through 11.8.4, and 11.9.0; non-guest team membership and archive-import access are required.

The record

CVE
CVE-2026-14259
Published
Sep 14, 2026
Updated
Sep 14, 2026
Vendor
Mattermost
Product
Mattermost
Classifications
Unavailable
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.11.0 <=10.11.22
  2. Affected versionversion=11.7.0 <=11.7.7
  3. Affected versionversion=11.8.0 <=11.8.4
  4. Affected versionversion=11.9.0 <=11.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=10.11.0 <=10.11.22; version=11.7.0 <=11.7.7; version=11.8.0 <=11.8.4; version=11.9.0 <=11.9.0

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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