For those enterprise IT managers who've been eagerly anticipating the next major WinAmp security flaw, the wait is over. Brett Moore of Security-Assessment.com on Tuesday published details of a security hole allowing attackers to take over a PC when a user visits a specially crafted Web page. The bug, a boundary error in the "IN_CDDA.dll" file, is the latest in a string of serious vulnerabilities in WinAmp, including an August flaw in the handling of "skin" files which attackers began to exploit before it had been discovered by researchers. The new bug, the skin file flaw and an April flaw in the handling of ".xm" files could all be exploited by luring an affected user to a website containing a specific type of file, which would then be automatically downloaded and executed.

This week's bug can be exploited in a number of ways, the most dangerous being via an ".m3u" playlist file, according to Moore. "When hosted on a website, these files will be automatically downloaded and opened in winamp without any user interaction," he wrote in Security-Assessment.com's advisory. "This is enough to cause the overflow that would allow a malicious playlist to overwrite EIP and execute arbitrary code."

Nullsoft, part of America Online, has patched the bug in WinAmp version 5.06, available from the company's website. Danish security firm Secunia, which maintains a vulnerabilities database, said the bug was "highly critical", its second most serious ranking.

The August vulnerability was WinAmp's most serious this year because it was exploited before a patch was available. While not as widely used as Windows Media Player or RealPlayer, WinAmp has an installed base of several million, including on corporate desktops, according to the company. The bug affected version 5.04, which was only a month old at the time.