CVE-2021-40565 in GPAC
Summary
by MITRE • 01/13/2022
A Segmentation fault caused by a null pointer dereference vulnerability exists in Gpac through 1.0.1 via the gf_avc_parse_nalu function in av_parsers.c when using mp4box, which causes a denial of service.
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Analysis
by VulDB Data Team • 01/15/2022
The vulnerability identified as CVE-2021-40565 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 gf_avc_parse_nalu function located within the av_parsers.c source file. The issue becomes exploitable when the mp4box utility processes malformed or specially crafted input files, leading to a complete system crash and subsequent denial of service condition that disrupts legitimate user operations and system availability.
The technical root cause of this vulnerability stems from inadequate input validation within the Advanced Video Coding parsing component of Gpac. When the gf_avc_parse_nalu function encounters certain malformed data structures during mp4box processing, it fails to properly check for null pointer conditions before attempting to dereference memory addresses. This null pointer dereference triggers an immediate segmentation fault that terminates the mp4box process and potentially impacts any dependent services or applications relying on Gpac functionality for multimedia processing. The vulnerability operates at the application level and specifically targets the video codec parsing mechanisms that handle AVC/H.264 encoded content streams.
From an operational perspective, this vulnerability presents a significant risk to systems that depend on Gpac for multimedia processing tasks including video transcoding, format conversion, and content delivery operations. Attackers could exploit this weakness by crafting malicious media files or manipulating input parameters to trigger the segmentation fault, thereby causing denial of service conditions that disrupt legitimate business operations. The impact extends beyond simple service interruption as it can affect automated workflows, content management systems, and streaming services that rely on stable multimedia processing capabilities. Organizations using Gpac in production environments face potential downtime and service degradation risks that could affect user experience and operational efficiency.
The vulnerability aligns with CWE-476, which specifically addresses null pointer dereference conditions in software systems, and demonstrates how improper error handling can lead to complete system failure. From an ATT&CK framework perspective, this vulnerability could be leveraged as part of a broader attack chain targeting system availability through denial of service vectors. The most effective mitigations involve immediate patching of Gpac to version 1.0.2 or later where the null pointer dereference has been corrected. Additionally, implementing input validation measures, restricting file upload capabilities, and employing sandboxing techniques for multimedia processing can provide defense-in-depth strategies. System administrators should also consider monitoring for异常 process termination patterns and implementing robust error handling within applications that utilize Gpac libraries to minimize the impact of such vulnerabilities on overall system stability and availability.