CVE-2026-51244 in ESP32-audioI2S
Summary
by MITRE • 07/27/2026
schreibfaul1 ESP32-audioI2S 3.4.5 has a buffer overflow vulnerability in UnpackFrameHeader(). Multiple attacker-controlled index parameters are used to access static and heap table arrays without range limitation. Invalid index values lead to out-of-bounds memory writing and heap buffer overflow.
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Analysis
by VulDB Data Team • 07/27/2026
The schreibfaul1 ESP32-audioI2S library version 3.4.5 contains a critical buffer overflow vulnerability within the UnpackFrameHeader() function that presents significant security risks for embedded audio processing systems. This vulnerability stems from inadequate input validation mechanisms that fail to constrain attacker-controlled index parameters when accessing both static and heap-based table arrays. The flaw represents a classic case of improper bounds checking where multiple indices derived from external inputs are directly used as array accessors without prior range verification or sanitization.
The technical implementation of this vulnerability occurs when the UnpackFrameHeader() function processes audio frame headers containing malformed data that includes invalid index values. These indices are typically extracted from audio stream payloads or configuration parameters and are subsequently used to access internal arrays containing audio codec configurations, sample rates, or channel mappings. When these indices exceed the allocated array boundaries, they trigger out-of-bounds memory writes that can overwrite adjacent memory locations including stack variables, return addresses, or heap-allocated data structures. This behavior aligns with CWE-129, which specifically addresses improper validation of array indices, and CWE-787, covering out-of-bounds write conditions.
The operational impact of this vulnerability extends beyond simple memory corruption scenarios to potentially enable remote code execution within the constrained environment of ESP32 microcontrollers. An attacker who can craft malicious audio streams or configuration data could exploit this vulnerability to overwrite critical program state information, leading to arbitrary code execution or system crashes. The heap buffer overflow aspect particularly concerning as it can corrupt heap metadata structures used for memory management, potentially causing heap corruption that may be exploited to achieve more sophisticated attack vectors including privilege escalation or denial of service conditions.
This vulnerability affects embedded audio applications running on ESP32 platforms that utilize the schreibfaul1 audioI2S library for processing audio streams. The attack surface includes IoT devices, smart speakers, audio recording equipment, and any system where audio data is processed through I2S interfaces. The exploitation requires minimal privileges as the vulnerability exists within the application's audio processing pipeline rather than requiring elevated system access. The impact is particularly severe in environments where these devices are exposed to untrusted audio sources such as network streams, external storage media, or user-provided content.
Mitigation strategies should focus on immediate code-level fixes including bounds checking for all index parameters derived from external inputs before array access operations. Implementing proper input validation routines that verify index ranges against array dimensions can prevent the out-of-bounds memory writes. Additionally, defensive programming practices such as using safe array access functions, implementing stack canaries, and enabling heap metadata protection mechanisms should be considered. The recommended approach aligns with ATT&CK technique T1068 which addresses local privilege escalation through memory corruption vulnerabilities. Organizations should also implement network segmentation for audio processing systems, deploy intrusion detection systems monitoring for anomalous audio stream patterns, and maintain updated firmware repositories to ensure timely patch deployment across deployed devices.