CVE-2023-50120 in GPAC
Summary
by MITRE • 01/10/2024
MP4Box GPAC version 2.3-DEV-rev636-gfbd7e13aa-master was discovered to contain an infinite loop in the function av1_uvlc at media_tools/av_parsers.c. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted MP4 file.
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Analysis
by VulDB Data Team • 06/17/2025
The vulnerability identified as CVE-2023-50120 affects MP4Box GPAC version 2.3-DEV-rev636-gfbd7e13aa-master and represents a critical denial of service weakness that can be exploited through carefully crafted MP4 media files. This issue resides within the media_tools/av_parsers.c source code file where the av1_uvlc function contains a logic flaw that creates an infinite loop condition. The vulnerability specifically targets the parsing of AV1 video codec data within MP4 container format files, making it particularly dangerous for multimedia processing applications that rely on GPAC for media handling and conversion tasks.
The technical implementation of this vulnerability stems from improper input validation within the av1_uvlc function which processes unsigned variable length codes used in the AV1 video compression standard. When a maliciously constructed MP4 file containing malformed AV1 data is processed by MP4Box, the parser enters an infinite loop during the decoding of variable length code sequences. This occurs because the function fails to properly handle edge cases in the bitstream parsing logic, causing the loop condition to never terminate. The vulnerability is classified under CWE-835 which specifically addresses infinite loops in software implementations, making it a direct manifestation of improper loop termination logic. The attack vector requires only the delivery of a specially crafted MP4 file to the target system, making it particularly dangerous for automated processing systems or web applications that handle user-uploaded media content.
The operational impact of this vulnerability extends beyond simple service disruption as it can effectively render systems unusable for extended periods. When exploited, the infinite loop consumes excessive CPU resources and can cause complete system hang or application crash, particularly affecting multimedia servers, content delivery networks, and media processing pipelines that utilize GPAC for format conversion and streaming. The vulnerability is especially concerning in environments where automated media processing workflows are prevalent, as it can lead to cascading failures across dependent systems. From an adversarial perspective, this weakness aligns with ATT&CK technique T1499.004 which involves network denial of service attacks through resource exhaustion, making it a potential vector for both accidental and intentional disruption of multimedia services.
Mitigation strategies for CVE-2023-50120 should focus on immediate patching of the affected GPAC version to the latest stable release that contains the corrected parsing logic. Organizations should implement strict input validation and sanitization measures for all incoming media files, particularly those containing AV1 codec data, to prevent malicious files from reaching the parser stage. Network-level protections such as rate limiting and file type validation can help reduce the attack surface while implementing proper timeout mechanisms in media processing workflows prevents indefinite resource consumption. Additionally, system administrators should consider deploying intrusion detection systems that monitor for unusual CPU utilization patterns that may indicate exploitation attempts. The vulnerability highlights the importance of robust error handling in multimedia parsing libraries and demonstrates the critical need for comprehensive testing of edge cases in codec implementations to prevent similar issues in future releases.