CVE-2017-8540: in the CISA KEV catalogue
Microsoft Malware Protection Engine Improper Restriction of Operations Vulnerability. CISA added CVE-2017-8540 to the Known Exploited Vulnerabilities catalogue on 2022-03-03 with a default due date of 2022-03-24. Known ransomware campaign use: Unknown. Forensic triage flag: No.
The Microsoft Malware Protection Engine running on Microsoft Forefront and Microsoft Defender on 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, and Windows Server 2016, Microsoft Exchange Server 2013 and 2016, does not properly scan a specially crafted file leading to memory corruption. aka "Microsoft Malware Protection Engine Remote Code Execution Vulnerability". (CISA description)
- Vendor / product
- Microsoft Malware Protection Engine
- CWE
- CWE-119
- CISA required action
- Apply updates per vendor instructions.
- EPSS
- 72%, percentile 99 (scored 2026-11-03)
EPSS puts about 72 in 100 odds (72%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 99% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.
Vendor and reference links (from CISA)
Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.
Frequently asked questions
Is CVE-2017-8540 in the CISA KEV catalogue?
Yes. CISA added CVE-2017-8540 (Microsoft Malware Protection Engine Improper Restriction of Operations Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2022-03-03. CISA's default due date for it is 2022-03-24.
Is CVE-2017-8540 used in ransomware attacks?
CISA marks known ransomware campaign use as Unknown for CVE-2017-8540. That means CISA lacks confirmation, not that ransomware groups do not use it.
What should I do about CVE-2017-8540?
CISA's required action: Apply updates per vendor instructions.
Sources
- CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
- FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
- NVD record for CVE-2017-8540