Integer Underflow Vulnerability in Microsoft Defender by Microsoft
CVE-2026-55011

7.8HIGH

Key Information:

Vendor

Microsoft
Status
Microsoft Malware Protection Engine
Vendor
CVE Published:
14 July 2026

What is CVE-2026-55011?

An integer underflow vulnerability in Microsoft Defender enables an unauthorized attacker to potentially execute arbitrary code on the local system. This flaw occurs due to improper handling of integer values, leading to unexpected behavior that could be exploited for malicious actions. Keeping Microsoft Defender updated is essential to mitigate risks associated with this vulnerability.

Affected Version(s)

Microsoft Malware Protection Engine 1.1.0.0 < 1.1.26060.3008

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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