
Attach (recommended) or Link to PDF file here:
[NAPEN16171380959.pdf](https://github.com/mozilla/pdf.js/files/6143802/NAPEN16171380959.pdf)

Configuration:
- Web browser and its version: Firefox 88 Nightly
- Operating system and its version: Windows 10
- PDF.js version:
- Is a browser extension: No

What went wrong? (add screenshot)
![](https://user-media-prod-cdn.itsre-sumo.mozilla.net/uploads/images/2021-03-15-10-58-27-ce2796.png)


var streamBytesLength = streamBytes.length;
    var signatureLength = signature.length;
    var scanLength = streamBytesLength - signatureLength;
    var i = startIndex,
      j,
      found = false;
    while (i < scanLength) {
      j = 0;
      while (j < signatureLength && streamBytes[i + j] === signature[j]) {
        j++;
      }
      if (j >= signatureLength) {
        
        i += j;
        while (i < streamBytesLength && isWhiteSpace(streamBytes[i])) {
          i++;
        }
        found = true;
        break;
      }
      i++;
    }
    return {
      found,
      length: i,
    };
  }
  function getHeaderBlock(stream, suggestedLength) {