CVE-2015-5122 in Flash Player
Summary
by MITRE
Use-after-free vulnerability in the DisplayObject class in the ActionScript 3 (AS3) implementation in Adobe Flash Player 13.x through 13.0.0.302 on Windows and OS X, 14.x through 18.0.0.203 on Windows and OS X, 11.x through 11.2.202.481 on Linux, and 12.x through 18.0.0.204 on Linux Chrome installations allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via crafted Flash content that leverages improper handling of the opaqueBackground property, as exploited in the wild in July 2015.
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Analysis
by VulDB Data Team • 04/22/2026
The CVE-2015-5122 vulnerability represents a critical use-after-free flaw within Adobe Flash Player's ActionScript 3 implementation that specifically targets the DisplayObject class. This vulnerability manifests in multiple Flash Player versions across different operating systems including Windows, OS X, and Linux platforms. The flaw occurs when the player processes crafted Flash content that manipulates the opaqueBackground property inappropriately, creating a scenario where memory locations are accessed after they have been freed by the application's memory management system. The vulnerability's exploitation potential extends beyond simple denial of service to enable remote code execution, making it particularly dangerous for widespread deployment.
The technical root cause of this vulnerability stems from improper memory management within the Flash Player's ActionScript 3 runtime environment. When Flash content manipulates the opaqueBackground property of DisplayObject instances, the application fails to properly validate or manage the memory references associated with these objects. This creates a use-after-free condition where an attacker can control the memory layout and potentially inject malicious code into the freed memory space. The vulnerability operates at the intersection of memory corruption and code execution, leveraging the inherent complexity of Flash Player's object model and memory management systems. According to CWE classification, this corresponds to CWE-416: Use After Free, which is a well-established category of memory safety vulnerabilities that have historically led to significant security compromises in software systems.
The operational impact of CVE-2015-5122 extends far beyond typical memory corruption scenarios, as it enables attackers to achieve arbitrary code execution on vulnerable systems. This capability allows threat actors to bypass traditional security controls, escalate privileges, and potentially establish persistent access to compromised systems. The vulnerability's exploitation in the wild during July 2015 demonstrated its effectiveness in real-world attacks, with attackers crafting malicious Flash content that could be delivered through various vectors including email attachments, compromised websites, and social engineering campaigns. The widespread adoption of Flash Player across different platforms and browsers made this vulnerability particularly attractive to attackers seeking broad impact. From an ATT&CK framework perspective, this vulnerability maps to multiple techniques including T1059.007: Command and Scripting Interpreter: JavaScript and T1068: Exploitation for Privilege Escalation, as it enables initial compromise and subsequent system control.
Mitigation strategies for CVE-2015-5122 require immediate action from organizations to address the vulnerability through multiple defensive layers. The most effective immediate response involves applying Adobe's security patches and updates to all affected Flash Player versions, as these releases contain the necessary code modifications to prevent the improper memory handling that leads to the use-after-free condition. Organizations should also implement network-level controls such as content filtering and web application firewalls to block access to known malicious Flash content. Additionally, security teams should consider disabling Flash Player entirely in their environments where possible, as the vulnerability landscape for Flash has significantly deteriorated over time. The remediation process should include thorough vulnerability scanning to identify all systems running affected Flash Player versions and comprehensive testing of patches to ensure they do not introduce compatibility issues with existing applications. Regular security monitoring and incident response procedures should be enhanced to detect potential exploitation attempts, as the vulnerability's characteristics make it suitable for both targeted attacks and mass exploitation campaigns.