Medium severity · published Feb 16, 2026
CVE-2026-1046
Arbitrary application execution via unvalidated server-controlled URLs in Help menu
6.5
CVSS
0.3%
EPSS
No
On KEV
Description
Mattermost Desktop App versions <=6.0 6.2.0 5.2.13.0 fail to validate help links which allows a malicious Mattermost server to execute arbitrary executables on a user’s system via the user clicking on certain items in the Help menu Mattermost Advisory ID: MMSA-2026-00577
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 18% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
through 6.2.0; through 5.2.13 · source: vendor
MD
Mattermost Desktop · Mattermost
5.13.0 before 5.13.3; 6.0.0 before 6.0.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-1046
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-1046
Vendor Advisory
https://mattermost.com/security-updates
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