In response to 0.0.0.0 day, Firefox Nightly version 131 had introduced a new security measure: blocking access to 0.0.0.0/::/::ffff:0.0.0.0 addresses. This change is currently live for Nightly users and will be gradually rolled out to all release users in the near future. Before we implement this ch...
Um, OK? I dunno why you’d wanna block access to that IP.
The first hyperlink in that post explains exactly why:
https://www.oligo.security/blog/0-0-0-0-day-exploiting-localhost-apis-from-the-browser
Oh man, I thought, it was some silly celebration day for the 0.0.0.0 address, so I didn’t even click on the link at first.
If a remote page can cause your browser to do fetches on your local machine, it can potentially poke at a lot of important stuff that has Web UIs running on the local machine.