CVE-2017-8558Microsoft Malware Protection Engine Memory Corruption
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…
Published Jun 29, 2017 · Updated May 12, 2026
Key Facts
Patch immediately- CVE-2017-8558 is a high-severity vulnerability (CVSS 7.8 v3) affecting Endpoint Protection (Microsoft), Forefront Endpoint Protection (Microsoft), Security Essentials (Microsoft) and 3 more products.
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 44% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Scores
CVSS v3
7.8
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
44%
Higher than 98.7% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
45/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
1
Proof-of-concept links
In-the-wild evidence
0
Reports of active use
Advisories And Exploit References
- advisoryhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-8558
- advisory42264
- advisory99262
- advisory1038783
- advisory1038784
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".
Affected Products
7 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Endpoint ProtectionMicrosoft | See advisory | n/a |
| Forefront Endpoint ProtectionMicrosoft | 2010 | n/a |
| Security EssentialsMicrosoft | See advisory | n/a |
| Windows DefenderMicrosoft | See advisory | n/a |
| Windows Intune Endpoint ProtectionMicrosoft | See advisory | n/a |
Timeline
Publicly disclosed
Jun 29, 2017
Last updated
May 12, 2026
Weakness Type
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
References
- advisoryportal.msrc.microsoft.com · CVE-2017-8558
- advisory42264
- advisory99262
- advisory1038783
- advisory1038784
FAQ
Common Questions.
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…
Affected: Endpoint Protection (Microsoft); Forefront Endpoint Protection (Microsoft) versions 2010; Security Essentials (Microsoft), among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Is CVE-2017-8558 On Your Attack Surface?
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