CVE-2007-0776 in Firefox
Summary
by MITRE
Heap-based buffer overflow in the _cairo_pen_init function in Mozilla Firefox 2.x before 2.0.0.2, Thunderbird before 1.5.0.10, and SeaMonkey before 1.0.8 allows remote attackers to execute arbitrary code via a large stroke-width attribute in the clipPath element in an SVG file.
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability identified as CVE-2007-0776 represents a critical heap-based buffer overflow affecting multiple Mozilla applications including Firefox 2.x before 2.0.0.2, Thunderbird before 1.5.0.10, and SeaMonkey before 1.0.8. This flaw resides within the _cairo_pen_init function which processes SVG (Scalable Vector Graphics) elements, specifically targeting the clipPath element with large stroke-width attributes. The vulnerability falls under CWE-121 Heap-based Buffer Overflow, which is classified as a fundamental memory safety issue where data written to heap memory exceeds the allocated buffer boundaries, potentially leading to memory corruption and arbitrary code execution.
The technical exploitation of this vulnerability occurs when a malicious SVG file containing a clipPath element with an excessively large stroke-width attribute is processed by the affected applications. The _cairo_pen_init function fails to properly validate the stroke-width parameter before allocating memory for the pen structure, allowing attackers to write beyond the intended buffer limits. This memory corruption can overwrite adjacent heap memory regions, potentially corrupting pointers, function return addresses, or other critical data structures. The attack vector is entirely remote, requiring only that a user open or view the malicious SVG file, making it particularly dangerous in web browsing contexts where users may unknowingly encounter such files.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the ability to gain complete control over the affected application's execution environment. Successful exploitation could result in arbitrary code execution with the privileges of the running application, potentially leading to full system compromise. The vulnerability affects a wide range of Mozilla-based applications, making it particularly concerning for organizations relying on these platforms for email and web browsing. Attackers could leverage this flaw to deliver malware, perform privilege escalation, or establish persistent access points within target networks, particularly in environments where users frequently interact with web content.
Mitigation strategies for CVE-2007-0776 primarily focus on immediate patch application, as the vulnerability was resolved through version updates that implemented proper input validation and buffer size checks in the _cairo_pen_init function. Organizations should prioritize updating to Mozilla Firefox 2.0.0.2, Thunderbird 1.5.0.10, and SeaMonkey 1.0.8 or later versions. Additional defensive measures include implementing content filtering solutions that scan SVG files for suspicious attributes, enabling strict security policies for web content rendering, and educating users about the risks of opening untrusted SVG files. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 Command and Scripting Interpreter: JavaScript and T1203 Exploitation for Client Execution, as it enables attackers to execute arbitrary code through web-based exploitation. Network administrators should also consider implementing web application firewalls and monitoring for unusual SVG file access patterns to detect potential exploitation attempts.