Firefox 77.0.1 released to patch a potential DDoS flaw

by Don Sharpe
Don Sharpe
Don Sharpe
Don has been writing professionally for over 10 years now, but his passion for the written word started back in his elementary school days. His work has been... read more
Affiliate Disclosure
  • Mozilla released Firefox 77.0.1 to fix a bug affecting one of its DoH service providers.
  • The solution should enable the wider-scale testing of DoH in the Firefox browser.
  • Fed up with persistent bugs while browsing the web? Be sure to check out our Browser Errors section for practical solutions!
  • As always, you may head on over to the Firefox page for more updates to the browser.
Firefox version 77.0.1
Instead of fixing issues with Firefox, upgrade to a better browser: Opera You deserve a better browser ! 350 million people use Opera daily, a fully-fledged navigation experience that comes with various built-in packages, enhanced resource consumption and great design.Here's what Opera can do:
  • Easy migration: use the Opera assistant to transfer exiting Firefox data, in just a few steps
  • Optimize resource usage: your RAM memory is used more efficiently than Firefox does
  • Enhanced privacy: free and unlimited VPN integrated
  • No ads: built-in Ad Blocker speeds up loading of pages and protects against data-mining
  • Download Opera

When Firefox 77.0 went live on June 2, 2020, it came with a bunch of goodies. One of its most notable new features, WebRender, got pushed to more Windows 10 laptops.

In addition, the new version introduced the about:certificate page, on which users can conveniently manage web certificates.

However, it turns out that this major update had a mission-critical flaw that called for quick remedial action. The folks at Mozilla responded by issuing Firefox 77.0.1 to address the bug.

Mozilla releases Firefox 77.0.1

Version 77.0.1 contains only a single fix. According to the update’s release notes, the patch turns off the automatic selection of DNS over HTTPS (DoH) providers when performing tests.

Disabled automatic selection of DNS over HTTPS providers during a test to enable wider deployment in a more controlled way.

DoH is a user privacy protocol that more and more tech companies are incorporating into their app solutions.

So, when testing DoH on Firefox, a bug was causing something of a Distributed Denial of Service (DDoS) situation. The problem affected NextDNS, one of the companies that Mozilla brought on board to provide DoH services.

The bug would cause the provider’s network to overload, preventing the wider-scale deployment of the protocol in any test run.

A contributor to Mozilla’s Bugzilla forum added this about the DoH flaw:

We need to be able to roll this out gradually so that we don’t overload any providers. Even the dry-run involves up to 10 requests per client which can be very significant when the entire release population updates.

Firefox 78 is the next major browser update from Mozilla. When it hits the release channel, it should offer improvements like the ability to check out blocked web resources.

Have you updated to Firefox 77 yet? If you have, are there any notable browser performance issues? You can always let us know in the comments section below.

Still having issues? Fix them with this tool:


If the advices above haven't solved your issue, your PC may experience deeper Windows problems. We recommend downloading this PC Repair tool (rated Great on to easily address them. After installation, simply click the Start Scan button and then press on Repair All.

This article covers:Topics: