A heap-based buffer overflow vulnerability (CVE-2026-51271) has been identified in the ESP32-audioI2S library version 3.4.5 by schreibfaul1. The flaw resides in the WAV header parsing function read_WAV_Header(), which fails to properly validate or restrict untrusted chunk size and bytes-to-skip values read from WAV files. Abnormally large values for 'bts' and 'headerSize' variables trigger out-of-bounds heap memory read and write operations during header parsing. This vulnerability can be exploited by an attacker supplying a maliciously crafted WAV file to achieve arbitrary code execution, sensitive information disclosure, denial of service, or privilege escalation. The affected library is commonly used in ESP32-based IoT audio applications. The issue stems from a lack of reasonable range checks on externally supplied data before use in memory operations. No patch status is noted in the advisory.