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Vulnerability record · CVE-2026-55012 · published 14 July 2026

CVE-2026-55012: Microsoft malware protection engine heap-based buffer overflow vulnerability

Microsoft · Malware Protection Engine

Integer overflow or wraparound in Microsoft Defender allows an unauthorized attacker to execute code locally.

7.8 CVSS 3.1 High EPSS 0.47% · top 62.1% CWE-122 · Heap-based buffer overflowCWE-190 · Integer overflow
7.8CVSS 3.1 base score
0.47%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References
24 Jul 2026Last modified by NVD

Description

Integer overflow or wraparound in Microsoft Defender allows an unauthorized attacker to execute code locally.

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55012 Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.8CVE-2026-41091Microsoft Defender link following allows local privilege elevationMicrosoft Defender's malware protection engine resolves links improperly before accessing files, a link-following flaw (CWE-59). A local attacker wit…KEVEPSS 0.44%analysed7.8CVE-2017-8540Microsoft Malware Protection Engine out-of-bounds write via crafted fileThe Microsoft Malware Protection Engine, used by Windows Defender, Forefront, Security Essentials, System Center Endpoint Protection, Intune Endpoint…KEVEPSS 72%analysed9.3CVE-2013-1346Microsoft malware protection engine memory buffer overflow vulnerabilitympengine.dll in Microsoft Malware Protection Engine before 1.1.9506.0 on x64 platforms allows remote attackers to execute arbitrary code or cause a d…EPSS 12%9.3CVE-2006-5270Microsoft antigen vulnerabilityInteger overflow in the Microsoft Malware Protection Engine (mpengine.dll), as used by Windows Live OneCare, Antigen, Defender, and Forefront Securit…EPSS 30%8.1CVE-2026-45584Microsoft malware protection engine heap-based buffer overflow vulnerabilityHeap-based buffer overflow in Microsoft Defender allows an unauthorized attacker to execute code over a network.EPSS 0.71%7.8CVE-2026-69414Microsoft malware protection engine improper access control vulnerabilityMicrosoft is aware of an elevation of privilege in the Microsoft Malware Protection Engine in Microsoft Defender publicly referred to as "Shield…EPSS 0.33%7.8CVE-2026-55011Microsoft malware protection engine vulnerabilityInteger underflow (wrap or wraparound) in Microsoft Defender allows an unauthorized attacker to execute code locally.EPSS 0.47%7.8CVE-2021-42298Microsoft malware protection engine code injection vulnerabilityMicrosoft Defender Remote Code Execution VulnerabilityEPSS 5.8%

Source: NIST National Vulnerability Database (record CVE-2026-55012), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.