How severe is CVE-2017-8558?

CVE-2017-8558 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-8558 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 44% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-8558?

CVE-2017-8558 primarily affects Microsoft Windows Defender. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-8558?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2017-8558 published?

CVE-2017-8558 was published on 2017-06-29 and last updated on 2026-06-17.

CVE-2017-8558

CVE-2017-8558 is a high-severity vulnerability in Microsoft Windows Defender with a CVSS 3.x base score of 7.8. Its EPSS exploit-prediction score of 44% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-119.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 9.3
EPSS exploit prediction: 44% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Microsoft Windows Defender
Published: 2017-06-29
Last modified: 2026-06-17

Description

The Microsoft Malware Protection Engine running on Microsoft Forefront and Microsoft Defender on 32-bit versions of Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703 does not properly scan a specially crafted file leading to memory corruption. aka "Microsoft Malware Protection Engine Remote Code Execution Vulnerability".

Frequently asked questions

What is CVE-2017-8558?: The Microsoft Malware Protection Engine running on Microsoft Forefront and Microsoft Defender on 32-bit versions of Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703 does not properly scan a specially crafted file leading to memory corruption. aka "Microsoft Malware Protection Engine Remote Code Execution Vulnerability".
How severe is CVE-2017-8558?: CVE-2017-8558 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-8558 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 44% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-8558?: CVE-2017-8558 primarily affects Microsoft Windows Defender. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-8558?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2017-8558 published?: CVE-2017-8558 was published on 2017-06-29 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:microsoft:windows_defender:-:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:endpoint_protection:-:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:forefront_endpoint_protection:-:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:forefront_endpoint_protection:2010:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:security_essentials:-:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:windows_intune_endpoint_protection:-:*:*:*:*:*:*:*

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