{"id":"CVE-2026-55011","title":"Microsoft Defender Remote Code Execution Vulnerability","summary":"Integer underflow (wrap or wraparound) in Microsoft Defender allows an unauthorized attacker to execute code locally.","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C","cvssSource":"cna","cwe":["CWE-191"],"vendor":"Microsoft","product":"Microsoft Malware Protection Engine","affected":["malware_protection_engine >= 1.1.0.0 < 1.1.26060.3008"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-07-13T00:00:00+00:00"},"published":"2026-07-14","updated":"2026-09-17","sourceUpdated":"2026-09-17T22:29:04.198Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-55011","references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55011","label":"Microsoft Defender Remote Code Execution Vulnerability"}],"tags":["cve.org"],"epss":0.00374,"epssPercentile":0.31314,"ingestedAt":"2026-09-08T17:06:31.929Z","slug":"CVE-2026-55011","body":"## Overview\n\nInteger underflow (wrap or wraparound) in Microsoft Defender allows an unauthorized attacker to execute code locally.\n\n## Affected\n\n- `malware_protection_engine >= 1.1.0.0 < 1.1.26060.3008`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}