Untrusted search path vulnerability in Nullsoft Winamp 5.581, and probably other versions, allows local users, and possibly remote attackers, to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse wnaspi32.dll that is located in the same folder as a .669, .aac, .aiff, .amf, .au, .avr, .b4s, .caf or .cda file.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6874
http://www.cs.ucdavis.edu/research/tech-reports/2010/CSE-2010-2.pdf