CVE-2009-4257: Realnetworks Helix Player

High severity, CVSS 9.3. EPSS: 8.5% chance of exploitation in the next 30 days.

Heap-based buffer overflow in datatype/smil/common/smlpkt.cpp in smlrender.dll in RealNetworks RealPlayer 10, RealPlayer 10.5 6.0.12.1040 through 6.0.12.1741, RealPlayer 11 11.0.0 through 11.0.4, RealPlayer Enterprise, Mac RealPlayer 10 and 10.1, Linux RealPlayer 10 and 11.0.0, and Helix Player 10.x and 11.0.0 allows remote attackers to execute arbitrary code via an SMIL file with crafted string lengths.

Affected products

• Realnetworks Helix Player: version 10.0 only; version 11.0.0 only; version 11.0.1 only
• Realnetworks Realplayer: version 10.0 only; version 10.5 only; version 11.0 only; version 11.0.1 only; version 11.0.2 only; version 11.0.3 only; …
• Realnetworks Realplayer Enterprise: any version
• Realnetworks Realplayer SP: version 1.0.0 only; version 1.0.1 only

Published 2010-01-25. Last modified 2026-06-16.