CVE-2026-1046Network attack vector

Application execution via unvalidated Help links

Published Feb 16, 2026 · Updated Feb 16, 2026

Improper custom-URL authorization in Mattermost Desktop App 5.13.2 and 6.0.0 through 6.0.2 allows remote attackers to run applications. The Help-menu link handler accepts a server-controlled target without validating the custom URL scheme before handing it to the operating system. Exploitation requires control of a connected Mattermost server and a user click on an affected Help item, after which an arbitrary local executable can launch.

CVSS severity7.6
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper custom-URL authorization in Mattermost Desktop App 5.13.2 and 6.0.0 through 6.0.2 allows remote attackers to run applications. The Help-menu link handler accepts a server-controlled target without validating the custom URL scheme before handing it to the operating system. Exploitation requires control of a connected Mattermost server and a user click on an affected Help item, after which an arbitrary local executable can launch.

The record

CVE
CVE-2026-1046
Published
Feb 16, 2026
Updated
Feb 16, 2026
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-939, T1204.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 16, 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=0 <=5.2.13
  2. Affected versionversion=0 <=6.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=5.2.13; version=0 <=6.2.0

Published CVSS scores

7.6Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:L
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

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-939Improper Authorization in Handler for Custom URL Scheme
T1204.001Malicious Link

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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