You might rest assured after setting a Master Password in the Firefox web browser, but it’s not as secure as you think. Last year, Mozilla did a major overhaul of their browser in the form of Firefox Quantum. But the non-profit forgot to fix the security holes that exist in their ‘very fast’ web browser for nine years.
The encryption scheme used for the Master Password feature is efficient enough, and it can be easily brute-forced, according to the security Wladimir Palant who is the creator of AdBlock Plus. Surprisingly, the issue wasn’t discovered recently but nine years ago when it was reported on the Mozilla bug tracker.
Read more about the flaw in Firefox’s Password Manager on Bleeping Computer.