Edge digits in PDF bug

In one of the weirdest — but equally dangerous — bugs of all time, it appears that Edge will display one set of numbers on the screen, but will send another set of numbers to the printer, effectively replacing content on your documents.

The bug was reported last week and was already confirmed by Microsoft. According to the user who first spotted the issue, the bug appears when Edge users are trying to print PDF documents via the browser’s built-in “Microsoft Print To PDF,” which is the default printing method when pressing CTRL+P in Edge.

Edge prints "114447" instead of "123456"

This currently unknown issue scrambles digits in a PDF document. For example, a simple sequence like “123456” will be replaced by “114447.” See image above for a visual representation of the issue.

To make matters worse, Edge is also the default application for viewing (and indirectly printing) PDF documents on Windows 10.

The person who reported the problem says he reproduced the bug on Microsoft Edge 38.14393.1066.0 running the Microsoft EdgeHTML engine 14.14393, but also on Microsoft Edge 40.15063 running EdgeHTML 15.15063.

The issue does not affect scanned documents in PDF form (which are basically like compressed images), but native and interactive PDF files only.

Users advised to use another app to print PDF documents

Microsoft has assigned this issue to an engineer to get it fixed. For the time being, it’s best if users use another application for printing PDF documents.

One user who also confirmed the issue on his Edge installation said he resolved his quandary by switching to Adobe Acrobat Reader for the time being.

Back in 2015, security expert David Kriesel revealed in a talk at the Chaos Communication Congress a similar issue affecting Xerox photocopiers, which were replacing random digits in printed documents.

Both issues, Edge and Xerox, are incredibly dangerous, as this could lead to customers sending incorrect invoices, the printing of construction plans with wrong measurements, or inaccurate metering of crucial, life-saving medicine, just to name a few of the most dangerous scenarios.