CVE-2015-8438

Vulnerability

A heap-based buffer overflow vulnerability exists in Adobe Flash Player before 18.0.0.268, 19.x and 20.x before 20.0.0.228 on Windows and OS X, and before 11.2.202.554 on Linux, as well as in Adobe AIR before 20.0.0.204 and related SDKs. The issue occurs when a crafted XML object is mishandled during a toString call [1]. This affects Flash Player versions 18.0.0.268 and earlier, 19.x up to 19.0.0.245, 20.x up to 20.0.0.227, and AIR/SDK versions before 20.0.0.204.

Exploitation

An attacker can exploit this vulnerability by convincing a user to visit a malicious web page or open a malicious file (e.g., via email or a crafted SWF). No special network position beyond normal web access is required; the attacker hosts a page with a crafted Flash file that triggers the heap overflow when the toString method is called on a malicious XML object [1]. The exploit requires user interaction (the target must browse to the malicious page or open the file).

Impact

Successful exploitation allows an attacker to execute arbitrary code within the context of the current process, typically the web browser or Flash player instance [1]. This can lead to complete compromise of confidentiality, integrity, and availability (CIA) of the affected system, potentially allowing installation of malware, data theft, or further lateral movement.

Mitigation

Adobe released fixed versions: Flash Player 20.0.0.228, AIR 20.0.0.204, AIR SDK 20.0.0.204, and for Linux Flash Player 11.2.202.554 [1][2]. Users should update immediately. For Gentoo Linux, the recommended upgrade is to >=www-plugins/adobe-flash-11.2.202.559 [2]. No workaround is available. This vulnerability (CVE-2015-8438) is distinct from CVE-2015-8446 and is not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog as of this writing.