CVE-2021-32278 in FAAD2
Summary
by MITRE • 09/20/2021
An issue was discovered in faad2 through 2.10.0. A heap-buffer-overflow exists in the function lt_prediction located in lt_predict.c. It allows an attacker to cause code Execution.
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Analysis
by VulDB Data Team • 08/29/2025
The vulnerability identified as CVE-2021-32278 represents a critical heap buffer overflow condition within the faad2 audio decoding library version 2.10.0 and earlier. This flaw resides in the lt_prediction function located within the lt_predict.c source file, making it a significant security concern for systems that process audio content using this library. The issue stems from improper bounds checking during the execution of long-term prediction algorithms that are fundamental to audio decoding processes, particularly affecting AAC audio formats. This vulnerability classifies under CWE-121 as a heap-based buffer overflow, where insufficient validation of input data allows attackers to write beyond allocated memory boundaries.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious audio files that trigger the vulnerable lt_prediction function during normal decoding operations. The heap buffer overflow enables arbitrary code execution, allowing remote attackers to potentially take complete control of affected systems. This type of vulnerability is particularly dangerous in environments where automated audio processing occurs, such as media servers, streaming platforms, or multimedia applications that accept user-uploaded content. The ATT&CK framework categorizes this as a code execution vulnerability under the technique of "Exploitation for Client Execution" and "Command and Control" activities, as it can lead to full system compromise.
The operational impact of CVE-2021-32278 extends beyond simple denial of service scenarios, as it creates a pathway for persistent malicious activities within affected systems. Systems utilizing faad2 for audio processing, including but not limited to multimedia applications, web browsers, mobile devices, and embedded systems, face potential compromise. The vulnerability's exploitation requires minimal prerequisites, as it can be triggered through normal audio file processing without requiring special privileges. This makes it particularly attractive to attackers targeting a wide range of applications that depend on the faad2 library for audio decoding functionality.
Mitigation strategies for this vulnerability include immediate patching of affected systems to upgrade to faad2 version 2.10.1 or later, which contains the necessary fixes for the heap buffer overflow. Organizations should implement input validation measures to filter potentially malicious audio files before processing, alongside network segmentation and monitoring to detect anomalous audio processing activities. The implementation of address space layout randomization, stack canaries, and other exploit mitigation techniques can further reduce the risk of successful exploitation. Additionally, regular security assessments and vulnerability scanning should be conducted to identify other potential instances of similar buffer overflow vulnerabilities within the software ecosystem, particularly in libraries and components that handle untrusted input data.