CVE-2016-5264 in Firefox
Summary
by MITRE
Use-after-free vulnerability in the nsNodeUtils::NativeAnonymousChildListChange function in Mozilla Firefox before 48.0 and Firefox ESR 45.x before 45.3 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via an SVG element that is mishandled during effect application.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 09/09/2022
The vulnerability CVE-2016-5264 represents a critical use-after-free flaw in Mozilla Firefox's handling of SVG elements, specifically within the nsNodeUtils::NativeAnonymousChildListChange function. This vulnerability affects Firefox versions prior to 48.0 and Firefox ESR 45.x versions prior to 45.3, creating a significant security risk for users of these affected releases. The issue stems from improper memory management when processing SVG elements during effect application, where the application fails to properly handle the lifecycle of memory objects that have already been freed, creating opportunities for malicious code execution or system instability.
The technical root cause of this vulnerability can be classified as CWE-416, which specifically addresses use-after-free conditions in software development. When an SVG element is processed during effect application, the nsNodeUtils::NativeAnonymousChildListChange function manipulates memory objects that may be freed while still being referenced by subsequent operations. This memory corruption occurs during the handling of anonymous child nodes in SVG documents, where the application does not properly validate that referenced objects remain valid in memory. The flaw manifests when the application attempts to access memory that has already been deallocated, leading to unpredictable behavior that can be exploited by attackers.
From an operational perspective, this vulnerability presents a severe threat to user security and system stability. Remote attackers can leverage this use-after-free condition to execute arbitrary code on vulnerable systems, potentially leading to complete system compromise. The heap memory corruption resulting from this flaw can be exploited through carefully crafted SVG content delivered via web pages, making it particularly dangerous in web browser environments where users frequently encounter untrusted content. The vulnerability's impact extends beyond simple denial of service, as it enables attackers to perform privilege escalation, data exfiltration, and persistent system compromise through carefully constructed attack vectors.
The exploitation of this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the Tactic of Execution and Defense Evasion. Attackers can leverage this flaw through web-based delivery methods, using malicious SVG content that triggers the vulnerable code path during normal browser operation. The vulnerability's characteristics make it particularly suitable for zero-day exploits in targeted attacks, as the use-after-free condition can be reliably triggered through SVG elements that are commonly encountered in web content. Organizations should prioritize immediate patching of affected Firefox versions to prevent exploitation attempts, as the vulnerability provides attackers with a direct path to arbitrary code execution.
Mitigation strategies for CVE-2016-5264 primarily focus on immediate software updates and security configuration hardening. The most effective remediation involves upgrading to Firefox 48.0 or later versions, or Firefox ESR 45.3 and later releases, where the memory management issues have been addressed through proper object lifecycle handling. System administrators should implement automated patch management processes to ensure all affected browsers are updated promptly, as the vulnerability's exploitability makes it a high-priority target for attackers. Additionally, organizations may consider implementing content security policies that restrict SVG content processing or deploy web application firewalls that can detect and block malicious SVG elements before they reach vulnerable browser components. The vulnerability underscores the importance of regular security updates and proper memory management practices in browser security implementations.