CVE-2019-14778 in VLC Media Player
Summary
by MITRE
The mkv::virtual_segment_c::seek method of demux/mkv/virtual_segment.cpp in VideoLAN VLC media player 3.0.7.1 has a use-after-free.
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Analysis
by VulDB Data Team • 12/11/2023
The vulnerability identified as CVE-2019-14778 represents a critical use-after-free flaw within the VideoLAN VLC media player version 3.0.7.1. This issue resides in the mkv::virtual_segment_c::seek method located in the demux/mkv/virtual_segment.cpp source file, which is responsible for handling Matroska media file demultiplexing operations. The flaw manifests when the application processes specific malformed or crafted Matroska files that trigger improper memory management during the seeking operation within virtual segments of these media containers.
The technical nature of this vulnerability stems from improper memory deallocation and subsequent access patterns within the demultiplexer component. When VLC encounters a specially crafted Matroska file, the virtual_segment_c::seek method executes code paths that lead to freeing memory resources while still maintaining references to them, creating a scenario where subsequent operations attempt to access already freed memory locations. This classic use-after-free condition can result in arbitrary code execution or application crashes, depending on the specific memory layout and timing of the access patterns. The vulnerability is particularly concerning as it occurs during normal media playback operations, making it exploitable through user interaction with malicious media files.
The operational impact of this vulnerability extends beyond simple application instability, presenting significant security risks to users who may encounter crafted media files through various attack vectors including email attachments, web downloads, or malicious streaming content. Attackers could leverage this flaw to execute arbitrary code on vulnerable systems with the privileges of the user running VLC, potentially leading to full system compromise. The vulnerability affects the core demultiplexer functionality, meaning any media file processed through VLC's Matroska handling capabilities could serve as an attack vector, making this a widespread concern for users who rely on VLC for media playback across different operating systems and platforms. This type of vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software implementations.
Mitigation strategies for CVE-2019-14778 primarily focus on immediate software updates and patches provided by VideoLAN, as the vulnerability exists within the application's core processing logic. Users should prioritize updating to VLC versions 3.0.8 or later, where the memory management issues have been addressed through proper resource handling and null pointer checks. Additionally, organizations should implement defensive measures such as restricting media file types that can be processed through VLC, particularly in environments where untrusted media content is encountered. Network administrators should consider implementing content filtering solutions that can identify and block potentially malicious media files before they reach end-user systems. The vulnerability demonstrates the importance of proper memory management in multimedia applications and aligns with ATT&CK technique T1203, which covers exploitation of memory corruption vulnerabilities, emphasizing the need for robust input validation and memory safety practices in media processing software to prevent similar issues in the future.