CVE-2026-55012

Microsoft Defender Remote Code Execution Vulnerability

Published Jul 14, 2026 CVSS 3.1 · 7.8 High EPSS < 1% KEV · Not listed
Description
Integer overflow or wraparound in Microsoft Defender allows an unauthorized attacker to execute code locally.

Analysis

AI-generated

Technical impact

Integer overflow or wraparound in the Windows Defender Malware Protection Engine allows an attacker with local system access to run arbitrary code. The flaw originates from improper handling of unsigned integer values and buffer boundaries, corresponding to the weaknesses identified by CWE-122 and CWE-190. Successful exploitation would enable the attacker to execute code in the Defender process, potentially leading to broader system compromise.

Affected Systems

The vulnerability targets the Microsoft Malware Protection Engine component of Microsoft Defender. All installations that include this engine could be impacted; however, the CVE data does not specify affected product versions, so it is unclear which specific releases are vulnerable.

Risk and Exploitability

The CVSS score of 7.8 signals a high‑severity local code‑execution flaw, while the EPSS score indicates a low probability of exploitation in the wild. Based on the description, the likely attack vector is local, requiring an attacker to supply crafted input to the Defender engine; no remote exploitation has been reported.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the security update released by Microsoft that fixes the integer overflow and wraparound flaw in the Defender engine, as documented at the Microsoft update guide.
  • Enable Defender Exploit Guard or activate memory‑corruption mitigations such as Memory Integrity in Windows Security settings.
  • Implement least‑privilege on local accounts and restrict local access to the Defender engine binaries and configuration files.

Generated by OpenCVE AI on August 1, 2026 at 09:49 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Integer overflow or wraparound in Microsoft Defender allows an unauthorized attacker to execute code locally.
Title Microsoft Defender Remote Code Execution Vulnerability
First Time appeared Microsoft
Microsoft malware Protection Engine
Weaknesses CWE-122
CWE-190
CPEs cpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft malware Protection Engine
References
Metrics cvssV3_1

{'score': 7.8, 'vector': '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'}

Weaknesses
  • CWE-122

    Heap-based Buffer Overflow

  • CWE-190

    Integer Overflow or Wraparound

Sources

Status
PUBLISHED
Assigner
microsoft
Published
Updated
Nov 10, 2026, 10:35 PM
Reserved
Jun 16, 2026, 2:12 PM
Status
Analyzed
Published
Jul 14, 2026, 5:17 PM
Modified
Oct 24, 2026, 9:10 PM