CVE-2009-4248 in RealPlayer
Summary
by MITRE
Buffer overflow in the RTSPProtocol::HandleSetParameterRequest function in client/core/rtspprotocol.cpp 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 Helix Player 10.x allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted RTSP SET_PARAMETER request.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 04/29/2026
The vulnerability identified as CVE-2009-4248 represents a critical buffer overflow flaw within the RealNetworks RealPlayer media playback software ecosystem. This issue resides in the RTSPProtocol::HandleSetParameterRequest function located in the client/core/rtspprotocol.cpp source file, affecting multiple versions of RealPlayer across different platforms including Windows, Mac, and Linux operating systems. The vulnerability manifests when the application processes crafted RTSP SET_PARAMETER requests, which are part of the Real Time Streaming Protocol used for controlling media streams. The flaw specifically occurs during the handling of parameter setting operations within the RTSP protocol implementation, making it particularly dangerous as it can be triggered through network-based attacks without requiring local system access.
The technical exploitation of this buffer overflow vulnerability stems from inadequate input validation within the RTSP protocol handler. When a maliciously crafted RTSP SET_PARAMETER request is received, the application fails to properly bounds-check the incoming data before copying it into a fixed-size buffer. This oversight allows attackers to overflow the allocated buffer space and overwrite adjacent memory locations, potentially corrupting program execution flow. The vulnerability's classification as a stack-based buffer overflow aligns with CWE-121, which describes conditions where data is copied into a buffer without proper bounds checking, leading to memory corruption. The attack vector is particularly concerning as it operates over network protocols, enabling remote code execution or denial of service conditions without requiring user interaction or physical access to the target system.
The operational impact of CVE-2009-4248 extends beyond simple application crashes, presenting significant security risks to organizations and individual users. The vulnerability can be exploited to cause complete application instability leading to denial of service conditions, effectively preventing legitimate users from accessing media content through RealPlayer. More critically, the buffer overflow condition creates opportunities for arbitrary code execution, allowing attackers to gain unauthorized control over affected systems. This risk is elevated when considering that RealPlayer was widely deployed across enterprise environments and consumer systems, making the potential attack surface extensive. The vulnerability's presence in both desktop and enterprise versions of RealPlayer, including specialized implementations like Helix Player, indicates a systemic issue within the software's protocol handling mechanisms that could affect multiple deployment scenarios.
Mitigation strategies for this vulnerability require immediate patch application from RealNetworks, as the company released security updates addressing the buffer overflow condition in affected versions. Network administrators should implement firewall rules and intrusion detection systems to monitor and block suspicious RTSP traffic patterns that could indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1203, which covers Exploitation for Execution, highlighting the need for defensive measures against remote code execution attacks. Organizations should also consider implementing network segmentation to limit exposure of systems running RealPlayer to untrusted networks, while maintaining regular security assessments to identify potential exploitation vectors. Additionally, user education regarding the risks of opening untrusted media content and the importance of keeping software updated plays a crucial role in reducing the attack surface for this and similar vulnerabilities.