CVE-2010-1028 in Firefox
Summary
by MITRE
Integer overflow in the decompression functionality in the Web Open Fonts Format (WOFF) decoder in Mozilla Firefox 3.6 before 3.6.2 and 3.7 before 3.7 alpha 3 allows remote attackers to execute arbitrary code via a crafted WOFF file that triggers a buffer overflow, as demonstrated by the vd_ff module in VulnDisco 9.0.
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Analysis
by VulDB Data Team • 05/03/2026
The vulnerability identified as CVE-2010-1028 represents a critical integer overflow flaw within the Web Open Fonts Format decoder of Mozilla Firefox versions prior to 3.6.2 and 3.7 alpha 3. This issue resides in the decompression functionality that processes WOFF files, which are designed to deliver web fonts with enhanced formatting capabilities and improved performance. The flaw specifically manifests when the decoder encounters maliciously crafted WOFF files that manipulate integer values during the decompression process, leading to predictable buffer overflow conditions. The vulnerability's exploitation pathway involves the vd_ff module within VulnDisco 9.0, which demonstrates how attackers can construct malformed WOFF content to trigger the overflow condition. This integer overflow vulnerability falls under CWE-190, which specifically addresses integer overflow conditions that can result in buffer overflows and arbitrary code execution. The technical implementation of this flaw involves the improper handling of size calculations during font decompression, where integer values representing buffer sizes or data lengths are manipulated to exceed maximum allowable values, causing the application to allocate insufficient memory for the decompressed font data.
The operational impact of this vulnerability extends beyond simple code execution, as it represents a severe remote code execution vector that could allow attackers to compromise user systems through web-based attacks. When a user visits a malicious website or opens a specially crafted WOFF file, the browser's font handling mechanism becomes vulnerable to exploitation. The integer overflow creates a condition where the application attempts to allocate memory blocks that are either too small to accommodate the decompressed data or cause memory corruption that can be leveraged for privilege escalation. This vulnerability directly aligns with ATT&CK technique T1059.007, which covers execution through scripting, as the exploitation can occur through web-based script execution. The flaw particularly affects users of older Firefox versions where the input validation and boundary checking mechanisms were insufficient to prevent malicious integer manipulation. Attackers can craft WOFF files that, when processed by the vulnerable decoder, cause memory corruption that can be exploited to overwrite critical program memory locations, potentially leading to full system compromise. The vulnerability's severity is compounded by the fact that WOFF files are commonly used in web design and can be easily embedded in web pages, making the attack surface broad and accessible.
Mitigation strategies for CVE-2010-1028 primarily focus on immediate version upgrades to patched Firefox releases, which contain proper integer overflow protections and enhanced input validation. Organizations should prioritize updating all affected Firefox installations to versions 3.6.2 or later, or 3.7 alpha 3 and beyond, where the integer overflow conditions have been addressed through improved boundary checking and size validation. The fix implemented by Mozilla typically involves strengthening the decompression logic to prevent integer overflows during size calculations and implementing robust input validation that checks for malicious size parameters before memory allocation occurs. Additionally, security administrators should consider implementing web content filtering solutions that can detect and block suspicious WOFF file content, particularly in environments where users may encounter untrusted web content. Network-based protections can include signature-based detection rules that identify malformed WOFF file structures commonly associated with this vulnerability. The implementation of sandboxing mechanisms and privilege separation can further reduce the potential impact of successful exploitation attempts, as these techniques limit the damage that can be caused by compromised browser processes. Regular security assessments and vulnerability scanning should include checks for outdated Firefox versions to ensure comprehensive protection against this and similar integer overflow vulnerabilities that could be exploited in similar web-based attack scenarios.