Vulnerability record

CVE-2015-1671

Microsoft Windows Remote Code Execution Vulnerability

HighExploitation confirmedCISA KEV

What should I do?

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run Windows, fix it now.

CISA required action: Apply updates per vendor instructions.

US federal civilian agencies must remediate by Jun 15, 2022.

Patch status

Official fix available since Sep 30, 2026

Apply the vendor's update to every affected system. Check the fixed-in versions below where known.

Basis: NVD patch reference

Patch or advisory on docs.microsoft.com (opens in a new tab)

Description

The Windows DirectWrite library, as used in Microsoft .NET Framework 3.0 SP2, 3.5, 3.5.1, 4, 4.5, 4.5.1, and 4.5.2; Office 2007 SP3 and 2010 SP2; Live Meeting 2007 Console; Lync 2010; Lync 2010 Attendee; Lync 2013 SP1; Lync Basic 2013 SP1; Silverlight 5 before 5.1.40416.00; and Silverlight 5 Developer Runtime before 5.1.40416.00, allows remote attackers to execute arbitrary code via a crafted TrueType font, aka "TrueType Font Parsing Vulnerability."

Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.

Affected products

Products affected by this vulnerability, with versions and the source of each entry
Product	Vendor	Affected versions	Source
.NET Framework	Microsoft	3.0; 4.0; 4.5; 4.5.1; 4.5.2; 3.5.1	NVD
Silverlight	Microsoft	5.0	NVD
Windows	Microsoft	—	KEV

Sources: NVD = NIST National Vulnerability Database; KEV = CISA Known Exploited Vulnerabilities catalog.

Intelligence timeline

Developments from the last 30 days, newest first.

CVSS scoredUpdateKEVSep 30, 2026
CVE-2015-1671 scored CVSS 7.8: Microsoft Windows, Microsoft Windows Remote Code Execution Vulnerability
CISA lists this as exploited in the wild. Unpatched Windows systems are exposed to active attacks now.
Basis: NIST National Vulnerability Database
Patch releasedUpdateKEVSep 30, 2026
Patch released for CVE-2015-1671: Microsoft Windows, Microsoft Windows Remote Code Execution Vulnerability
An official fix is now available for Microsoft Windows. This vulnerability is being exploited, so apply it promptly.
Basis: NVD patch reference

1 earlier event is available with a subscription. See plans.

Coverage

We have not published a story about this vulnerability yet.

References

nvd.nist.gov https://nvd.nist.gov/vuln/detail/CVE-2015-1671
securityfocus.com http://www.securityfocus.com/bid/74490
securitytracker.com http://www.securitytracker.com/id/1032281
docs.microsoft.com https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-044
cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2015-1671