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TI-2026-39718 Aliases CVE-2026-55011GHSA-9gvv-f74q-gxrr

Microsoft Defender Remote Code Execution Vulnerability

Priority LOW 36CWE-191Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from Microsoft.

Summary

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

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00466 40th percentileScored 2026-11-07
Fix Fixed Microsoft Malware Protection Engine (Microsoft): 1.1.26060.3008

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftMicrosoft Malware Protection Engine1.1.0.0 to before 1.1.26060.30081.1.26060.3008Patch availableCNA
  • Microsoft Malware Protection Engine VendorMicrosoft Affected 1.1.0.0 to before 1.1.26060.3008 Fixed in 1.1.26060.3008 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:*before 1.1.26060.3008VulnerableMicrosoft
  • cpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:* Versions before 1.1.26060.3008 Vulnerable ·Microsoft

Remediation

  • Fix · CNA Microsoft Malware Protection Engine (Microsoft) Fixed in 1.1.26060.3008

Vendor assessments

Microsoft

Microsoft's page for this CVE →

Impact
Remote Code Execution
Exploited
No
Publicly disclosed
No
Exploitability
Exploitation Less Likely
ProductStatusPlan or fix
Microsoft Malware Protection EngineFixed 1.1.26060.3008 · Security Update

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55011
  2. 2026-10-03 Alias added: GHSA-9gvv-f74q-gxrr

References

Patch 1

  • TI-2026-29727 Microsoft Defender Elevation of Privilege Vulnerability KEVCVSS 3.1HIGH 7.8
  • TI-2017-06074 Out-of-bounds write in Microsoft Malware Protection Engine KEVCVSS 3.1HIGH 7.8
  • TI-2017-00265 Memory corruption in Microsoft Malware Protection Engine CVSS 3.0HIGH 7.8
  • TI-2026-48742 Microsoft Defender Elevation of Privilege Vulnerability CVSS 3.1HIGH 7.8
  • TI-2026-37344 Microsoft Defender Elevation of Privilege Vulnerability CVSS 3.1HIGH 7.8
  • TI-2017-06072 Memory corruption in Microsoft Malware Protection Engine CVSS 3.0HIGH 7.8
See all 30 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences