In schreibfaul1 ESP32-audioI2S 3.4.5, a heap-based buffer overflow vulnerability exists in the latinToUTF8() character encoding conversion function. The functio…

A heap-based buffer overflow vulnerability (CVE-2026-51272) has been identified in the ESP32-audioI2S library version 3.4.5 by schreibfaul1. The flaw resides in the latinToUTF8() function, which handles Latin-1 to UTF-8 character encoding conversion. The function incorrectly calculates the required buffer size by simply doubling the input length, without enforcing strict boundary validation during heap buffer reallocation. An attacker supplying malicious oversized input can trigger insufficient buffer allocation, resulting in an out-of-bounds write condition. The potential impact includes remote code execution, information disclosure, denial of service, and privilege escalation. The vulnerability affects embedded IoT systems utilizing the ESP32 platform with this audio library. A proof-of-concept has been published on GitHub Gist. Developers are advised to review and patch the affected function with proper bounds checking.