Low severity · published May 18, 2026
CVE-2026-4643
Calling window.close() from server-side content causes crash in the Mattermost Desktop App
3.5
CVSS
0.2%
EPSS
No
On KEV
Description
Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent server-rendered content from closing an underlying application view in the Mattermost Desktop App which allows a malicious server or plugin to crash the desktop client via invoking {{window.close()}} in the renderer context, leading to a denial of service condition at the client level. Mattermost Advisory ID: MMSA-2026-00633
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 6% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
through 6.0.1; through 5.4.13 · source: vendor
MD
Mattermost Desktop · Mattermost
through 5.4.13.0; 6.0.0 through 6.0.1; 6.1.0 before 6.2.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-4643
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-4643
Vendor Advisory
https://mattermost.com/security-updates
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