In a blog post on Friday, Mike Shaver, Mozilla's VP of Engineering, explained why his company had decided to block Microsoft's .NET Framework Assistant add-on to the Firefox browser.

"It's recently surfaced that it has a serious security vulnerability, and Microsoft is recommending that all users disable the add-on," Shaver wrote. "Because of the difficulties some users have had entirely removing the add-on, and because of the severity of the risk it represents if not disabled, we contacted Microsoft today to indicate that we were looking to disable the extension and plugin for all users via our blocklisting mechanism."

And so Mozilla did just that, as you may have noticed over the weekend if you're a Firefox user. But as it turns out, the add-on may not be so harmful after all.

"We received confirmation from Microsoft this evening that the Framework Assistant add-on is not a mechanism for exploiting the vulnerabilities detailed in the earlier post, so we've removed it from the blocklist," Mozilla said.

Mozilla went on to say that the blocklist update propagates to clients, so if the add-on was previously disabled, it should  automatically re-enable, though you'll need to restart your browser for it to take effect.