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Denial of service in Microsoft Defender

Published: 2019-09-23
Severity Low
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2019-1255
Exploitation vector Network
Public exploit N/A
Vulnerable software
Microsoft Security Essentials
Client/Desktop applications / Antivirus software/Personal firewalls

Windows Defender
Client/Desktop applications / Antivirus software/Personal firewalls

Microsoft Forefront Endpoint Protection
Server applications / DLP, anti-spam, sniffers

Vendor Microsoft

Security Advisory

This security advisory describes one low risk vulnerability.

1) Input validation error

Severity: Low

CVSSv3: 3.2 [CVSS:3.0/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-1255

CWE-ID: CWE-20 - Improper Input Validation

Exploit availability: No


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of files within the Microsoft Malware Protection Engine in Microsoft Defender. A remote attacker can create a specially crafted file, trick the victim into executing it and prevent legitimate accounts from executing legitimate system binaries. 


Install updates from vendor's website.
This vulnerability was addressed in Microsoft Malware Protection Engine 1.1.16400.2.

Vulnerable software versions

Microsoft Security Essentials: -

Microsoft Forefront Endpoint Protection: 2010

Windows Defender: for Windows 8.1, for Windows 10, Windows 10 1511, Windows 10 1607, Windows Server 2016, Windows 10 1703, for Windows RT 8.1, on Windows 7 for 32-bit Systems Service Pack 1, on Windows Server 2008, on Windows Server 2012

CPE External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.