dcmjs is a JavaScript implementation of DICOM manipulation. Prior to 0.52.0, the DecimalString and IntegerString implementations in src/ValueRepresentation.js sanitize text with a permissive regular expression and pass the result to JavaScript's Number constructor without validating finiteness or the DICOM value-representation rules. Scientific notation overflow in a DS or IS field can produce positive or negative Infinity, while stripping alphabetic characters from signed infinity text can leave a sign-only string that converts to NaN. IntegerString also accepts exponent notation and values outside the DICOM signed 32-bit IS range. Applications that trust these parsed values can propagate invalid numbers into spatial geometry, display windowing, dose scaling, frame counts, rescaling, or volume reconstruction, causing incorrect calculations or disrupted processing. This issue is fixed in version 0.52.0.