CVE-2026-3117Network attack vector

Integration disruption via unchecked GitLab commands

Published May 18, 2026 · Updated May 18, 2026

Missing authorization in the Mattermost GitLab plugin allows remote authenticated users to disrupt integrations through administrative commands. The instance and webhook command handlers process normal-user requests without the administrator permission checks required to uninstall an instance or configure webhook connections. Any normal account that can issue slash commands can alter GitLab integration availability, but the published impact does not include data disclosure or broader server control.

CVSS severity6.5
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in the Mattermost GitLab plugin allows remote authenticated users to disrupt integrations through administrative commands. The instance and webhook command handlers process normal-user requests without the administrator permission checks required to uninstall an instance or configure webhook connections. Any normal account that can issue slash commands can alter GitLab integration availability, but the published impact does not include data disclosure or broader server control.

The record

CVE
CVE-2026-3117
Published
May 18, 2026
Updated
May 18, 2026
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-862, T1489
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 18, 2026CVE publishedPublication date reported by the CVE source.
  2. May 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <=10.13.11
  2. Affected versionversion=0 <=11.1.5
  3. Affected versionversion=0 <=11.3.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=10.13.11; version=0 <=11.1.5; version=0 <=11.3.4

Published CVSS scores

6.5Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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

CWE-862Missing Authorization
T1489Service Stop

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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