CVE-2015-1671: Microsoft DirectWrite TrueType Font Parsing Remote Code Execution

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 17 September 2026. Confidence: high.

critical priorityThe vulnerability is listed in CISA KEV, has a high EPSS score, and allows remote code execution with user interaction, making it a high-priority target for attackers.

What it is

The Windows DirectWrite library fails to properly handle crafted TrueType fonts, allowing memory corruption that can lead to arbitrary code execution. The flaw affects a wide range of Microsoft products including .NET Framework, Office, Lync, Live Meeting, and Silverlight. Because fonts are commonly processed automatically, this is a serious risk for unpatched systems.

Impact

An attacker who successfully exploits this vulnerability can execute arbitrary code in the context of the current user. If the user has administrative privileges, the attacker could take complete control of the affected system.

Attack surface

The vulnerability is reached when a user opens or previews a document, webpage, or application that renders a malicious TrueType font. User interaction is required, and no authentication is needed to trigger the flaw.

Exploitation

CVE-2015-1671 is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild. EPSS estimates a 54.6% probability of exploitation in the next 30 days, placing it in the 98.9th percentile.

What to do

• Apply the vendor patch referenced in Microsoft Security Bulletin MS15-044 immediately.
• Disable or restrict the use of untrusted TrueType fonts where feasible.
• Implement application whitelisting to block execution of untrusted binaries.
• Educate users to avoid opening suspicious documents or visiting untrusted websites.
• Monitor for and block known malicious font files at email and web gateways.

Detection

• Monitor for process creation events involving font rendering libraries (e.g., DirectWrite) loading unusual files.
• Scan for known malicious TrueType font files using updated antivirus signatures.
• Audit systems for missing MS15-044 patches using vulnerability management tools.
• Enable and review Windows Defender Exploit Guard or similar memory protection logs for anomalies.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.