CVE-2026-51266 in ESP32-audioI2S
Summary
by MITRE • 07/28/2026
schreibfaul1 ESP32-audioI2S 3.4.5 has a heap-based buffer overflow vulnerability in the HTTP request header construction logic. The application dynamically splices attacker-controlled host name, path, query string, and multiple HTTP header fields into a fixed ps_ptr heap buffer without proper size limitation and boundary validation. Remote attackers can use an oversized crafted network request parameter to trigger out-of-bounds heap write, leading to arbitrary code execution.
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Analysis
by VulDB Data Team • 07/28/2026
The schreibfaul1 ESP32-audioI2S 3.4.5 library presents a critical heap-based buffer overflow vulnerability that stems from improper input validation during HTTP request header construction. This vulnerability exists within the application's network processing logic where attacker-controlled data elements including hostname, path, query string, and multiple HTTP header fields are concatenated into a fixed-size ps_ptr heap buffer. The implementation lacks essential size limitation mechanisms and boundary validation checks that would normally prevent such memory corruption scenarios.
The technical flaw manifests through the absence of input sanitization and buffer size enforcement during the dynamic construction of HTTP headers. When the application processes network requests containing oversized crafted parameters, it fails to validate the cumulative size of concatenated attacker-controlled data against the predefined heap buffer limits. This allows remote attackers to exceed the allocated memory space and overwrite adjacent heap memory regions, creating potential for arbitrary code execution through controlled memory corruption.
This vulnerability operates under the attack pattern described by CWE-121 Heap-based Buffer Overflow, which specifically addresses buffer overflows occurring in heap memory allocations where insufficient bounds checking permits writes beyond allocated buffer boundaries. The operational impact extends beyond simple denial of service to potentially enable complete system compromise when attackers can manipulate the overflow to overwrite critical program control structures or return addresses within the application's execution flow. The remote exploitation nature means that an attacker does not require physical access to the device and can trigger the vulnerability through network-based requests.
The security implications of this vulnerability align with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, as attackers could potentially leverage heap corruption to execute malicious code on the affected ESP32 devices. The vulnerability affects embedded systems running audio streaming applications that utilize HTTP protocols for content delivery, making it particularly concerning for IoT deployments where such devices may be exposed to untrusted network traffic without proper input validation.
Mitigation strategies should include immediate implementation of input length validation and buffer size checking mechanisms within the HTTP header construction logic. Developers must enforce strict boundaries on concatenated string operations and implement proper memory allocation techniques that account for maximum possible input sizes. The recommended approach involves validating all attacker-controllable inputs against predetermined maximum lengths before concatenation, implementing stack canaries or heap canaries where applicable, and ensuring proper bounds checking during dynamic buffer manipulation. Additionally, regular security audits of embedded network processing components should be conducted to identify similar patterns of insecure memory handling that could lead to comparable vulnerabilities in other system components.