CVE-2015-2426

What Is the Windows Adobe Type Manager Library?

The Windows Adobe Type Manager Library (ATMFD.DLL) is a kernel-mode font rendering driver that processes OpenType (OTF) and PostScript Type 1 fonts. Unlike user-mode font handling, ATMFD.DLL processes font data directly in the Windows kernel — meaning any memory corruption in font parsing can directly produce kernel privilege escalation or, as in CVE-2015-2426, kernel-level remote code execution when triggered via a document or web page that loads a malicious font.

Overview

CVE-2015-2426 is a zero-day remote code execution vulnerability in the Windows Adobe Type Manager Library (ATMFD.DLL) that was exposed in the Hacking Team data breach of July 5, 2015. When ATMFD.DLL processes a specially crafted OpenType font — embedded in a document or served on a web page — kernel memory corruption enables arbitrary code execution. Because font rendering occurs in the kernel, exploitation directly achieves kernel-level code execution without a separate privilege escalation step. Microsoft released an emergency out-of-band patch MS15-078 on July 20, 2015, fifteen days after the zero-day was publicly exposed.

Affected Versions

Fixed in MS15-078 (July 20, 2015 emergency patch).

Technical Details

Root Cause: OpenType Font Memory Corruption in Kernel

CVE-2015-2426 involves a buffer overflow or memory corruption (CWE-119) in ATMFD.DLL's parsing of OpenType font tables. When Windows processes a specially crafted OTF font, the kernel-mode driver writes data beyond allocated bounds during font metric or glyph processing — corrupting adjacent kernel heap memory.

Because ATMFD.DLL runs in kernel context, this memory corruption directly affects kernel-mode data structures. An attacker who can trigger this font loading from any application — a browser, a document viewer, or Windows itself — achieves kernel code execution without any separate privilege escalation step.

The Hacking Team Breach

On July 5, 2015, Hacking Team — an Italian commercial spyware company — suffered a catastrophic data breach. Approximately 400 GB of internal data was published, including source code for their surveillance tools and, critically, working zero-day exploit code for several Windows vulnerabilities including CVE-2015-2426.

The public exposure of working exploit code created immediate mass exploitation risk — any threat actor could now use the zero-day. Microsoft responded with unusual speed, releasing the out-of-band emergency patch MS15-078 on July 20, 2015 — fifteen days after the breach — rather than waiting for the next Patch Tuesday (August 11).

The Hacking Team leak also exposed CVE-2015-2387 (ATMFD LPE, patched in Patch Tuesday MS15-077 the same week) and CVE-2015-5119 (Adobe Flash zero-day, see CVE-2015-5119).

Attack Characteristics

Discovery

Zero-day exploit code for CVE-2015-2426 was published in the Hacking Team data breach on July 5, 2015. Prior to the breach, the vulnerability had been identified and exploited by Hacking Team as part of their commercial spyware toolkit. After breach publication, multiple security researchers and threat actors had access to working exploit code within hours.

Exploitation Context

• Hacking Team commercial surveillance: Hacking Team sold their RCS (Remote Control System) surveillance software to government clients worldwide; CVE-2015-2426 was a zero-day in their exploit toolkit, likely used in government-sanctioned surveillance operations before the breach
• Immediate post-breach exploitation: Security researchers documented exploitation of CVE-2015-2426 within days of the breach, as threat actors adapted the Hacking Team exploit code
• Kernel-level impact: Because ATMFD.DLL processing occurs in the kernel, exploitation yields kernel code execution directly — making this one of the highest-impact Windows zero-days of 2015
• Emergency patch cycle: MS15-078 is notable as one of Microsoft's few emergency out-of-band patches in 2015, demonstrating the severity and exploitation urgency
• CISA KEV (2022): Added March 2022

Remediation

1. Apply MS15-078 (July 20, 2015 emergency patch). Systems updated after July 20, 2015 are protected.

2. Disable ATMFD.DLL as a workaround (if patching is delayed):

   HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows\DisableATMFD = 1
   

   This disables rendering of OpenType/Type1 fonts but eliminates the attack surface.

3. Keep Windows updated — any system on a current Windows Update schedule applied this fix years ago. Unpatched systems running Windows Vista/7/8.x without MS15-078 are at risk.

4. Upgrade to Windows 10 2004+ — Microsoft removed ATMFD.DLL from Windows 10 version 2004 (May 2020 Update) and later, permanently eliminating this attack surface.