AOL versions up to and including 9.5 includes an ActiveX control (Phobos.dll) that exposes a method called Import() via the Phobos.Playlist COM object. This method is vulnerable to a stack-based buffer overflow when provided with an excessively long string argument. Exploitation allows remote attackers to execute arbitrary code in the context of the user, but only when the malicious HTML file is opened locally, due to the control not being marked safe for scripting or initialization. AOL remains an active and supported brand offering services like AOL Mail and AOL Desktop Gold, but the legacy AOL 9.5 desktop software—specifically the version containing the vulnerable Phobos.dll ActiveX control—is long discontinued and no longer maintained.
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).