What’s Vulnerable › Vulnerabilities

CVE-2026-55011: Microsoft Defender Remote Code Execution Vulnerability

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-14 · updated 2026-10-28
• Weakness: CWE-191

Description

Integer underflow (wrap or wraparound) in Microsoft Defender allows an unauthorized attacker to execute code locally.

Affected products

• Microsoft Malware Protection Engine: before 1.1.26060.3008 — fixed in 1.1.26060.3008
• Microsoft Malware Protection Engine: from 1.1.0.0 before 1.1.26060.3008 — fixed in 1.1.26060.3008

How to fix

Upgrade to a fixed version: Microsoft Malware Protection Engine 1.1.26060.3008; Microsoft Malware Protection Engine 1.1.26060.3008. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55011

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