dcmjs, a JavaScript library for DICOM manipulation used in web-based medical imaging viewers, contains an input validation bypass in its handling of DS (Decimal String) and IS (Integer String) value representations. The DecimalString and IntegerString classes in ValueRepresentation.js use a regex sanitizer followed by JavaScript's Number() constructor. While the regex strips direct NaN/Infinity strings, it preserves scientific notation (including the 'e' character), enabling: 1. Infinity injection via scientific notation overflow (1e999999) 2. NaN injection via sign-only remnants from stripped inf strings ("-inf" -> "-") 3. IS accepting scientific notation in violation of PS3.5