Stack-based buffer overflow in protocol/rtsp/rtspclnt.cpp in RealNetworks RealPlayer 10; RealPlayer 10.5 6.0.12.1040 through 6.0.12.1741; RealPlayer 11 11.0.x; RealPlayer SP 1.0.0 and 1.0.1; RealPlayer Enterprise; Mac RealPlayer 10, 10.1, 11.0, and 11.0.1; Linux RealPlayer 10, 11.0.0, and 11.0.1; and Helix Player 10.x, 11.0.0, and 11.0.1 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via an ASM RuleBook with a large number of rules, related to an "array overflow."