ExifReader 4.40.0 can throw an uncaught "RangeError: Offset is outside the bounds of the DataView" while parsing crafted HEIC/AVIF files. The file only needs a valid leading "ftyp" box with a HEIC/AVIF major brand followed by a malformed ISO-BMFF box, such as an empty 8-byte "free" box or a truncated extended-size box. This is reachable through the public "ExifReader.load()" API for in-memory buffers and through the async file/URL loaders when an application parses attacker-supplied images. In applications that do not wrap every parse in a defensive try/catch, a single uploaded or fetched image can abort the request/worker and cause a denial of service. Credit requested: Yaohui Wang.