CVE-2017-5984 in libav
Summary
by MITRE
In libavcodec in Libav 9.21, ff_h264_execute_ref_pic_marking() has a heap-based buffer over-read.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 08/27/2025
The vulnerability identified as CVE-2017-5984 resides within the libavcodec component of Libav version 9.21, specifically within the ff_h264_execute_ref_pic_marking() function. This issue represents a heap-based buffer over-read that occurs during the processing of h264 video streams, making it a critical security concern for any system handling multimedia content. The flaw manifests when the decoder attempts to manage reference picture marking operations, which are essential for maintaining proper video frame referencing in h264 encoding standards. Such operations require careful memory management to ensure that reference frames are correctly tracked and managed throughout the decoding process.
The technical nature of this vulnerability stems from inadequate bounds checking within the reference picture marking implementation. When processing malformed h264 streams, the function fails to validate the size of reference picture lists before accessing memory locations, leading to unauthorized reads beyond the allocated buffer boundaries. This over-read condition can potentially expose sensitive memory contents, including stack data, heap metadata, or other application state information that may be accessible to an attacker. The vulnerability specifically affects the memory management routines that handle reference picture lists, which are fundamental to h264 decoding operations and video frame reconstruction processes. The flaw does not directly enable code execution but creates conditions where attackers could potentially extract information or manipulate memory access patterns.
From an operational impact perspective, this vulnerability poses significant risks to multimedia processing systems, streaming platforms, and content delivery networks that utilize Libav for video decoding. Attackers could exploit this weakness by crafting malicious h264 streams designed to trigger the buffer over-read condition, potentially leading to information disclosure or system instability. The vulnerability's classification under CWE-125 indicates it involves an out-of-bounds read, while its relationship to the broader ATT&CK framework places it within the reconnaissance and resource consumption categories, as attackers might use such flaws to gather system information or consume additional computational resources. Systems processing untrusted video content are particularly vulnerable, including web browsers, media players, and server-side video processing applications that rely on Libav for decoding operations.
Mitigation strategies for CVE-2017-5984 primarily involve upgrading to patched versions of Libav where the buffer over-read has been addressed through proper bounds checking and memory validation. Organizations should implement input validation measures that filter or sanitize h264 streams before processing, particularly when handling untrusted content from external sources. Additionally, deploying intrusion detection systems that monitor for anomalous multimedia processing patterns and implementing memory protection mechanisms such as stack canaries or address space layout randomization can help reduce the exploitability of this vulnerability. Security teams should also consider network segmentation and access controls to limit exposure of systems that process multimedia content, while maintaining regular vulnerability assessments to identify and remediate similar issues across their multimedia processing infrastructure.