PDF with NULL padding

Fixed Issue #7913814


System A.
Jun 16, 2016
This issue is public.
Reported by 2 people

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Steps to reproduce

This issue applies specifically to PDF documents that have been padded with NULL characters.

Although I can’t attest to the reasoning for creating a PDF with NULL padding, a software developer who makes one of our medical systems generates PDFs with a minimum file size.

By default, the PDF is padded with NULL characters after the .%%EOF string at the end of the file.

Edge seems to have trouble rendering these files. The problem is significantly pronounced when trying to open the file from a network share. Using wireshark to analyze the traffic, I see repeated requests to the SMB server for "AndX Request (0x2E)" where Edge is requesting the same 512 bytes at the same offset over the course of 110,000 requests. These bytes fall within the padding appended after the EOF. By comparison, the non-padded data is retrieved in 111 requests. This causes Edge to fail to render the PDF for about 5 minutes, while it struggles to make sense of the NULL data. Eventually, it does render.

I’m attaching three files that I’ve modified to illustrate the problem. The symptoms are the same, but I cannot send the original files because they contain medical information.

File 1) padding_after_eof is symptomatically the longest render time, with the most extraneous traffic

File 2) padding_before_eof also takes a while, but not as long as file 1

File 3) is a non-padded file, which loads instantly.


Comments and activity

  • Microsoft Edge Team

    Changed Assigned To to “Brad E.”

  • Hello,

    Thanks for the feedback on Edge.

    I am not able to repro this on my local workstation.  All 3 of the files load instantly for me. Which version of Edge are you using?

    All the best,
    The MS Edge Team

  • Please provide more information once you are able to in order to avoid having this item closed out as not repro.

    We appreciate you taking the time to provide us with your feedback on Edge.

  • Hey Brad,
    Thanks for looking into this. The delay was only really noticed when we started opening PDF files in Edge from a shared folder on the network. Workstations are connected with 10/100. File server is on a 4GB teamed virtual NIC.

    If it helps, I can do another capture with WireShark and upload it for you.


  • Microsoft Edge Team

    Changed Assigned To to “Rico M.”

  • I think this issue is a combination of things. I’ve produced steps to reproduce here. https://scriptimus.wordpress.com/2016/08/22/unable-to-open-pdf-in-edge/

    In this scenario I did not know why some files would open and others not. I’ve given examples of files that can reproduce the issue also.

  • Microsoft Edge Team

    Changed Assigned To to “Amit K.”

    Changed Assigned To from “Amit K.” to “Manoj B.”

    Changed Status to “Confirmed”

    Changed Title from “PDF with NULL padding” to “PDF with NULL padding”

    Changed Status from “Confirmed” to “Fixed”

  • This is now fixed and should be available in the public builds soon. Thank you for the feedback.

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