This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of RealNetworks Realplayer. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within the way RealPlayer handles ID3v2 Tags. RealPlayer creates a fixed size buffer for certain tags and will then populate them with the data from the file. It uses a call to WideCharToMultiByte to convert the data, but fails to take into account that converting a single wide char might result in more then two multi-byte chars. This causes more data to be written into the fixed buffer then anticipated resulting in a heap buffer overflow.