CVE-2026-122329 in SDL_mixer
Summary
by MITRE • 11/05/2026
SDL_mixer 3.1.2 through 3.2.4 contains a stack-based buffer overflow in FetchXLaw() in src/decoder_aiff.c due to miscalculated output offsets when expanding A-law or mu-law samples. Attackers can supply a crafted AIFF-C file that overwrites roughly 1 KB of adjacent stack memory when decoded, causing crashes or potential code execution.
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Analysis
by VulDB Data Team • 11/05/2026
The vulnerability identified in SDL_mixer versions 3.1.2 through 3.2.4 represents a critical security flaw rooted in improper input validation and boundary checking within the audio decoding subsystem. Specifically, the defect resides in the FetchXLaw function located in the src/decoder_aiff.c source file. This component is responsible for processing AIFF-C files that utilize A-law or mu-law compression formats, which are commonly used to reduce audio data size by applying non-linear quantization. The core technical issue arises from a miscalculation of output offsets during the expansion process where compressed samples are converted back into their uncompressed PCM format. When an attacker supplies a specially crafted AIFF-C file with malformed header information or corrupted sample data, the decoder fails to correctly calculate the necessary buffer space required for the expanded audio stream. This logical error leads directly to a stack-based buffer overflow condition.
From a technical perspective, this vulnerability is classified under CWE-121, which denotes a stack-based buffer overflow resulting from writing more data to a fixed-size buffer on the call stack than it can hold. The attacker exploits this by crafting an input file that triggers the miscalculation in FetchXLaw, causing the function to write approximately one kilobyte of data beyond the bounds of the allocated local variables and return address space. This overwrite corrupts adjacent memory locations on the execution stack, which typically contain critical control flow information such as saved frame pointers and return addresses. The magnitude of the overflow is significant enough to allow an attacker to manipulate these control structures effectively. Consequently, if the application continues execution after the corruption occurs, it may jump to arbitrary code controlled by the attacker rather than returning safely to the calling function.
The operational impact of this vulnerability extends beyond simple application instability. While a crash or denial of service is a likely immediate outcome due to segmentation faults triggered by memory access violations, the primary concern for security professionals is the potential for remote code execution. An adversary who can trick a user into opening a malicious AIFF-C file could achieve arbitrary code execution with the privileges of the process running SDL_mixer. This aligns with ATT&CK technique T1203, which covers exploitation for client-side execution, and potentially T1059 if the executed payload facilitates further command-and-control activities or lateral movement within a compromised environment. The risk is particularly acute in applications that automatically decode audio files upon loading, such as game engines, media players, or interactive multimedia software, where user interaction might be limited to simply opening a file provided by an attacker via phishing or malicious websites.
Mitigation strategies must address both immediate remediation and long-term defensive coding practices. The most effective solution is to apply the vendor-provided patch that updates SDL_mixer to version 3.2.5 or later, where this specific miscalculation in FetchXLaw has been corrected with proper bounds checking. For environments unable to update immediately, defense-in-depth measures should be implemented. These include enabling stack canaries and Address Space Layout Randomization (ASLR) at the operating system level to mitigate exploitation success rates by making it difficult for attackers to predict memory addresses. Additionally, deploying application whitelisting or restricting file type associations in sensitive environments can reduce the attack surface. Developers integrating SDL_mixer should also ensure that input validation is robust and consider using static analysis tools configured to detect buffer overflow patterns similar to CWE-120 during future code reviews to prevent recurrence of such logic errors in audio processing libraries.