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 media file.
The specific flaw exists in the parsing of GIF87a files over the streaming protocol RTSP. When specifying a large Screen Width size in the Screen Descriptor header a calculation on the destination heap chunks size is improperly checked for overflow. This leads to a smaller buffer being allocated and subsequently a heap overflow when processing the received data. Exploitation of this vulnerability can lead to system compromise under the credentials of the currently logged in user.