Microsoft Edge, the built-in replacement for Internet Explorer in Windows 10, is a fairly new browser compare to other options like Chrome and Firefox, as such, there is still a lot of flaws that need squashing out to make it a viable alternative. One such flaw, related to the InPrivate browsing feature, seems to have been fixed on the desktop in the latest cumulative update 1586.104, or KB3135173 as it's named in Windows Update .
InPrivate browsing is a common feature in modern browsers - Microsoft Edge included - that allows users to browse the web discreetly without leaving any traces on their computers in the form of history and cache files. A recent study by security firm Forensics Focus, which we reported on (the original seems to have been removed), however, found that at least in Microsoft Edge, the feature was not functioning as intended. By digging into the WebCache file in a user's hard drive, they found out that websites visited in InPrivate mode are still recorded in the file, albeit with some special signs.
This knowledge makes it possible for any individual computer-savvy enough to search through a computer and open files to get browsing history that's supposed to be anonymous. The matter is made more complicated by Edge's history syncing functionality across all devices through a Microsoft account, opening users to vulnerabilities and law enforcers to complications in identifying the right suspect, should such information is used for investigation.
Microsoft had acknowledged the issue, promising a fix "as quickly as possible", and it seems they have kept their promise in the newest update. We recently reported on the first ever full update changelog from Microsoft for Windows 10, and among all the fixed items, one stood out.
"Fixed issue with Microsoft Edge browser caching visited URLs while using InPrivate browsing."
-from Microsoft changelog for Windows 10 cummulative update 10586.104.
InPrivate browsing is a basic security feature that every modern browser must have, and while the initial bug was still inexcusable given the space Edge has to compete in, at least Microsoft has quickly provided a remedy. With the issue gone, Windows users have one less point to worry about when using Edge, and we look forward to more essential features being added to the future to finally get Edge on equal grounds with its competitors (looking at you, extension support).