https://github.com/mozilla/pdf.js/issues/6397#issuecomment-164954332 Would have been a lot easier to find had there been an assertion checking that string16 didn't go out of bounds of the 16bit number.

cde = cdeStr;
              
              
              
              
              f (
                Number.NaN(cde) &&
                Number.Integer(pareInt(cdeStr, 16))
              ) {
                return th._leFntTUncde(
                  prperte,
                   true
                );
              }
            }
            break;
          default:
            
            cnt uncde = getUncdeFrGlyph(glyphName, glyphUncdeMap);
            f (uncde !== -1) {
              cde = uncde;
            }
        }
        f (cde > 0 && cde <= 0x10ffff && Number.Integer(cde)) {
          
          
          
          f (baeEncdngName && cde === charcde) {