CVE-2021-40559 in GPAC
Summary
by MITRE • 01/13/2022
A null pointer deference vulnerability exists in gpac through 1.0.1 via the naludmx_parse_nal_avc function in reframe_nalu, which allows a denail 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 null pointer dereference vulnerability identified as CVE-2021-40559 represents a critical denial of service weakness within the gpac multimedia framework version 1.0.1 and earlier. This vulnerability specifically manifests within the naludmx_parse_nal_avc function located in the reframe_nalu component of the software architecture. The flaw occurs when the application attempts to access a memory location through a pointer that has not been properly initialized or validated, creating a scenario where the program execution terminates abruptly due to the attempted dereference of a null reference.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the video decoding and demultiplexing processes. When processing Advanced Video Coding (AVC) encoded media streams, the naludmx_parse_nal_avc function fails to properly verify that certain pointer variables contain valid memory addresses before attempting to access their contents. This condition typically arises when handling malformed or specially crafted video packets that do not conform to expected AVC stream specifications. The vulnerability is classified under CWE-476 as a null pointer dereference, which represents a common software flaw pattern that directly impacts application stability and availability.
Operational impact of this vulnerability extends beyond simple denial of service conditions to potentially compromise the entire multimedia processing pipeline within systems utilizing gpac. Attackers can exploit this weakness by constructing malicious video files or streams that trigger the specific code path leading to the null pointer dereference. When successful, this exploitation causes the target application to crash or terminate unexpectedly, effectively denying service to legitimate users who depend on the multimedia processing capabilities. The vulnerability's severity is particularly concerning in environments where gpac serves as a core component of video processing workflows, streaming platforms, or content delivery systems where uninterrupted operation is critical for service availability.
Mitigation strategies for CVE-2021-40559 should prioritize immediate patch application from the gpac development team, which typically involves implementing proper null pointer validation checks within the affected function. System administrators should also consider implementing input sanitization measures that filter or reject malformed video streams before they reach the vulnerable parsing components. Network-level protections can include implementing content inspection mechanisms that identify and block suspicious video packet structures that may trigger the vulnerability. Organizations should also establish monitoring protocols to detect unusual application crash patterns that may indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1499.004 as a denial of service via resource exhaustion, though in this case the mechanism operates through application-level crashes rather than resource depletion. Additionally, implementing robust error handling and defensive programming practices within the affected codebase would provide additional layers of protection against similar null pointer dereference scenarios in the future.