CVE-2021-40563 in GPAC
Summary
by MITRE • 01/13/2022
A Segmentation fault exists casued by null pointer dereference exists in Gpac through 1.0.1 via the naludmx_create_avc_decoder_config function in reframe_nalu.c when using mp4box, which causes a denial of service.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/15/2022
The vulnerability identified as CVE-2021-40563 represents a critical segmentation fault condition within the Gpac multimedia framework, specifically affecting versions through 1.0.1. This flaw manifests through a null pointer dereference in the naludmx_create_avc_decoder_config function located within the reframe_nalu.c source file. The issue occurs when the mp4box utility processes specific malformed input files, creating a scenario where the application attempts to access memory through a null pointer reference. Such conditions typically arise when the software fails to properly validate input data structures before attempting to dereference pointers, leading to abrupt program termination and system instability.
The technical implementation of this vulnerability stems from inadequate input validation within the AVC (Advanced Video Coding) decoder configuration creation process. When mp4box encounters malformed MP4 containers containing specific NALU (Network Abstraction Layer Unit) structures, the naludmx_create_avc_decoder_config function fails to properly initialize or validate pointer variables before accessing them. This null pointer dereference causes the application to crash with a segmentation fault, effectively rendering the utility unusable for its intended purpose. The flaw demonstrates characteristics consistent with CWE-476, which specifically addresses null pointer dereference vulnerabilities in software systems.
From an operational perspective, this vulnerability presents a significant denial of service risk to systems relying on Gpac for multimedia processing tasks. Attackers could exploit this condition by crafting malicious MP4 files designed to trigger the null pointer dereference during mp4box processing, thereby causing service disruption for legitimate users. The impact extends beyond simple application crashes as it affects the broader multimedia processing pipeline, potentially compromising workflows that depend on automated video handling. Organizations using Gpac for content processing, streaming, or conversion tasks face elevated risk of service interruptions when processing untrusted input files, creating operational challenges for content management systems and media processing servers.
Mitigation strategies for CVE-2021-40563 should prioritize immediate patch application from the Gpac development team, as the vulnerability directly impacts core functionality of the mp4box utility. System administrators should implement input validation measures at network boundaries, filtering MP4 files for malformed structures before processing through Gpac utilities. Additionally, deploying intrusion detection systems capable of identifying suspicious file patterns and implementing sandboxed processing environments can reduce the attack surface. Organizations should also consider implementing automated monitoring for application crashes and system instability related to multimedia processing tasks. The vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through application-level disruptions, emphasizing the need for robust input validation and error handling mechanisms in multimedia processing frameworks.