firefoxlogoMozilla has announced a new security tool for users of its Firefox web browser. Called Firefox Monitor, the website lets visitors check if their accounts have been included in known data breaches and the types of data exposed in each breach.

The security tool is the result of a partnership between Mozilla and HaveIBeenPwned.com (HIBP), a site set up by security researcher Troy Hunt that includes a database of email addresses that are known to have been compromised in data breaches.

Thanks to the partnership, Firefox is able to check email addresses against the HIBP database via a method of anonymized data sharing (full details can be found in Troy Hunt's blog post). The new tool builds on Firefox's existing HIBP integration, which tells users if a site they are visiting was previously exposed in a data breach.

Firefox Monitor Homepage2
In February, password management app 1Password announced its own partnership with HIBP, which lets users check that their passwords haven't been leaked online. Since that time, developers AgileBits have built the Pwned Passwords database list into its 1Password desktop apps. As of today, users can also search HIBP from directly within 1Password via the Watchtower feature in the web version of the product.

Mozilla says it will begin trialling the new integration between HIBP and Firefox to make breach data searchable over the coming weeks.

Firefox Quantum is available for macOS as a free download directly from the Mozilla website.

Top Rated Comments

bLackjackj Avatar
97 months ago
If they are creating a hash of my email it can be reversed engineered back to my email. No thanks.
No it can't,..I don't know where you are making up this information from, but it's wrong.
Score: 4 Votes (Like | Disagree)
mrzz Avatar
97 months ago
I used to like the old pre-Firefox, “Mozilla” browser. Remember that?
I'm fine with speed improvements in FF58+ I
If they are creating a hash of my email it can be reversed engineered back to my email. No thanks.
I recommend you to read something about hashes.
Score: 4 Votes (Like | Disagree)
woodlandtrek Avatar
97 months ago
If they are creating a hash of my email it can be reversed engineered back to my email. No thanks.
Firefox will not only hash your email with SHA-1, it will send only the first 6 characters of that hash to HIBP. That amount of data is useless to try to recreate your email.
Score: 1 Votes (Like | Disagree)
mikes63737 Avatar
97 months ago
Your e-mail could be brute-forced from the hash -- but it cannot be reversed.

Eg, the service could say "I have a hash abf112bacd3489... is this hash equal to a@gmail.com? No? How about b@gmail.com? No?"

However, nobody... NOBODY is going to take the time to brute-force each individual email/hash. It would take way too much time and effort.
Score: 1 Votes (Like | Disagree)
JosephAW Avatar
97 months ago
I'm assuming you can opt out of this "feature" where they send your email to this third party?
Score: 1 Votes (Like | Disagree)
tothsa Avatar
97 months ago
I'm assuming you can opt out of this "feature" where they send your email to this third party?
Did you read the full article? It says Mozilla uses “anonymized data sharing” so your email address won’t be revealed to third parties!
Score: 1 Votes (Like | Disagree)

Popular Stories

iOS 26

15 New Things Your iPhone Can Do in iOS 26.2

Friday December 5, 2025 9:40 am PST by
Apple is about to release iOS 26.2, the second major point update for iPhones since iOS 26 was rolled out in September, and there are at least 15 notable changes and improvements worth checking out. We've rounded them up below. Apple is expected to roll out iOS 26.2 to compatible devices sometime between December 8 and December 16. When the update drops, you can check Apple's servers for the ...
Intel Inside iPhone Feature

Apple's Return to Intel Rumored to Extend to iPhone

Friday December 5, 2025 10:08 am PST by
Intel is expected to begin supplying some Mac and iPad chips in a few years, and the latest rumor claims the partnership might extend to the iPhone. In a research note with investment firm GF Securities this week, obtained by MacRumors, analyst Jeff Pu said he and his colleagues "now expect" Intel to reach a supply deal with Apple for at least some non-pro iPhone chips starting in 2028....
ive and altman

Jony Ive's OpenAI Device Barred From Using 'io' Name

Friday December 5, 2025 6:22 am PST by
A U.S. appeals court has upheld a temporary restraining order that prevents OpenAI and Jony Ive's new hardware venture from using the name "io" for products similar to those planned by AI audio startup iyO, Bloomberg Law reports. iyO sued OpenAI earlier this year after the latter announced its partnership with Ive's new firm, arguing that OpenAI's planned "io" branding was too close to its...
iPhone 17 Pro Cosmic Orange

10 Reasons to Wait for Next Year's iPhone 18 Pro

Monday December 1, 2025 2:40 am PST by
Apple's iPhone development roadmap runs several years into the future and the company is continually working with suppliers on several successive iPhone models at the same time, which is why we often get rumored features months ahead of launch. The iPhone 18 series is no different, and we already have a good idea of what to expect for the iPhone 18 Pro and iPhone 18 Pro Max. One thing worth...
Photos App Icon Liquid Glass

John Gruber Shares Scathing Commentary About Apple's Departing Software Design Chief

Thursday December 4, 2025 9:30 am PST by
In a statement shared with Bloomberg on Wednesday, Apple confirmed that its software design chief Alan Dye will be leaving. Apple said Dye will be succeeded by Stephen Lemay, who has been a software designer at the company since 1999. Meta CEO Mark Zuckerberg announced that Dye will lead a new creative studio within the company's AR/VR division Reality Labs. On his blog Daring Fireball,...
maxresdefault

iPhone Fold: Launch, Pricing, and What to Expect From Apple's Foldable

Monday December 1, 2025 3:00 am PST by
Apple is expected to launch a new foldable iPhone next year, based on multiple rumors and credible sources. The long-awaited device has been rumored for years now, but signs increasingly suggest that 2026 could indeed be the year that Apple releases its first foldable device. Subscribe to the MacRumors YouTube channel for more videos. Below, we've collated an updated set of key details that ...
Apple John Ternus 2019

Will John Ternus Really Be Apple's Next CEO?

Friday December 5, 2025 9:01 am PST by
There is uncertainty about Apple's head of hardware engineering John Ternus succeeding Tim Cook as CEO, The Information reports. Some former Apple executives apparently hope that a new "dark-horse" candidate will emerge. Ternus is considered to be the most likely candidate to succeed Cook as CEO. The report notes that he is more likely to become CEO than software head chief Craig Federighi, ...
ios 18 to ios 26 upgrade

Apple Pushes iPhone Users Still on iOS 18 to Upgrade to iOS 26

Tuesday December 2, 2025 11:09 am PST by
Apple is encouraging iPhone users who are still running iOS 18 to upgrade to iOS 26 by making the iOS 26 software upgrade option more prominent. Since iOS 26 launched in September, it has been displayed as an optional upgrade at the bottom of the Software Update interface in the Settings app. iOS 18 has been the default operating system option, and users running iOS 18 have seen iOS 18...
iOS 26

Apple Seeds iOS 26.2 and iPadOS 26.2 Release Candidates to Developers and Public Beta Testers

Wednesday December 3, 2025 10:33 am PST by
Apple today seeded the release candidate versions of upcoming iOS 26.2 and iPadOS 26.2 updates to developers and public beta testers, with the software coming two weeks after Apple seeded the third betas. The release candidates represent the final versions of iOS 26.2 and iPadOS 26.2 that will be provided to the public if no further bugs are found during this final week of testing....
Johny Srouji

Apple Chip Chief Johny Srouji Could Be Next to Go as Exodus Continues

Sunday December 7, 2025 10:41 am PST by
Apple's senior vice president of hardware technologies Johny Srouji could be the next leading executive to leave the company amid an alarming exodus of leading employees, Bloomberg's Mark Gurman reports. Srouji apparently recently told CEO Tim Cook that he is "seriously considering leaving" in the near future. He intends to join another company if he departs. Srouji leads Apple's chip design ...