CVE-2010-0416 in RealPlayer
Summary
by MITRE
Buffer overflow in the Unescape function in common/util/hxurl.cpp and player/hxclientkit/src/CHXClientSink.cpp in Helix Player 1.0.6 and RealPlayer allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a URL argument containing a % (percent) character that is not followed by two hex digits.
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Analysis
by VulDB Data Team • 05/01/2026
The vulnerability identified as CVE-2010-0416 represents a critical buffer overflow flaw within the Helix Player 1.0.6 and RealPlayer software ecosystems. This security weakness resides in the Unescape function implementation across two key source files: common/util/hxurl.cpp and player/hxclientkit/src/CHXClientSink.cpp. The flaw manifests when the application processes URL arguments containing percent-encoded characters that do not conform to standard hexadecimal formatting requirements, creating a dangerous condition that can be exploited by remote attackers to compromise system integrity.
The technical nature of this vulnerability stems from improper input validation and memory management within the URL parsing routines of these media player applications. When a maliciously crafted URL contains a percent character followed by insufficient hexadecimal digits, the Unescape function fails to properly handle the malformed input, leading to memory corruption that can result in application crashes or potentially arbitrary code execution. This buffer overflow condition occurs because the application does not adequately check the length of hexadecimal sequences following percent characters before attempting to process them, allowing attackers to overwrite adjacent memory locations with controlled data.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass potential remote code execution capabilities that could enable attackers to gain unauthorized control over affected systems. When exploited successfully, the buffer overflow can cause the targeted media player applications to crash or behave unpredictably, potentially allowing attackers to inject and execute malicious code within the context of the running application. This represents a significant security risk for users who may unknowingly encounter malicious URLs while browsing the internet or accessing multimedia content through vulnerable applications.
Organizations and users affected by this vulnerability should implement immediate mitigations including prompt software updates to versions that address the buffer overflow conditions in the Unescape function implementations. System administrators should also consider network-level protections such as URL filtering and content validation to prevent exploitation attempts, while security teams should monitor for potential exploitation attempts through network traffic analysis. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and corresponds to ATT&CK technique T1203, focusing on the exploitation of input validation vulnerabilities for remote code execution. Additionally, this weakness demonstrates characteristics of T1059, where attackers leverage application vulnerabilities to execute malicious commands, making it essential for security teams to implement comprehensive patch management strategies and application whitelisting controls to protect against potential exploitation attempts.