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

Apple Shopping Event 2025

Apple Announces 2025 Black Friday Event, Here's What You Can Get

Thursday November 20, 2025 6:28 am PST by
Apple's annual four-day Black Friday through Cyber Monday shopping event is returning on Friday, November 28 through Monday, December 1 in many countries, including the United States, Canada, Australia, New Zealand, France, Germany, Italy, Spain, the United Kingdom, Belgium, the Netherlands, Sweden, Thailand, and others. During the shopping event, customers can get an Apple gift card with...
iPhone 17 Pro Cosmic Orange

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

Wednesday November 19, 2025 4:00 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...
iOS 26

Everything New in iOS 26.2 Beta 3

Monday November 17, 2025 3:20 pm PST by
Apple provided developers with the third beta of an upcoming iOS 26.2 update, and there are still new features that are being added with each beta that we get. We've rounded up all of the changes that Apple made in beta 3. AirDrop Apple added new AirDrop functionality, providing a way for two people to share files temporarily without having to add one another as contacts. iOS 26.2...
applecare apple care banner

Apple Brings New AppleCare+ Options to India

Tuesday November 18, 2025 8:42 am PST by
Apple today announced an expansion of AppleCare+ coverage in India, with new options for monthly and annual plans, and the addition of Theft and Loss for iPhone for the first time. Options for monthly and annual AppleCare+ plans in India provide more choice and flexibility, allowing users to keep coverage for as long as they require. Apple's vice president of Worldwide iPhone Product...
ipad mini 7 feature red and blue

iPad Mini 8: Four Major New Features to Expect

Wednesday November 19, 2025 7:50 am PST by
Apple's eighth-generation iPad mini is highly likely to arrive next year, offering a significant refresh of the device with at least four major new features. OLED Display The next-generation version of the iPad mini could feature an OLED display, as part of Apple's plan to expand the display technology across many more of its devices. Apple's first OLED device was the Apple Watch in 2015, ...
iPhone 17 Pro and Air N1 Feature

iPhone 17 vs. iPhone 16 Wi-Fi Speeds: New Study Reveals the Winner

Tuesday November 18, 2025 10:53 am PST by
A new study has revealed that the iPhone 17, iPhone 17 Pro, iPhone 17 Pro Max, and iPhone Air achieve significantly faster average Wi-Fi speeds compared to the iPhone 16 series, thanks to Apple's custom-designed N1 chip. The study was conducted by Ookla, the company behind the popular Speedtest website and app. It said the results are based on global, crowdsourced Speedtest user data...
Apple Wallet ID Illinois

iPhone Driver's License Feature Launching in Illinois

Tuesday November 18, 2025 8:47 am PST by
In select U.S. states, residents can add their driver's license or state ID to the Wallet app on the iPhone and Apple Watch, providing a convenient and contactless way to display proof of identity or age at select airports and businesses, and in select apps. Starting this Wednesday, November 19, the feature will be available to residents of Illinois. The announcement confirmed that the...
macbook black friday

The Best Early Black Friday Mac Deals

Tuesday November 18, 2025 7:32 am PST by
We're getting closer to Black Friday, which lands next week on Friday, November 28. In the lead-up to the shopping holiday, we're tracking a few lowest-ever prices on Apple's most popular Macs, including the M4 MacBook Air and brand new M5 MacBook Pro. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a purchase, we may receive a small payment,...
iOS 26

iOS 26.2 Adds These New Features to Your iPhone

Thursday November 20, 2025 10:50 am PST by
iOS 26.2 is currently in beta testing. The upcoming update includes a handful of new features and changes on the iPhone, including a new Liquid Glass slider for the Lock Screen's clock, offline lyrics for Apple Music, and more. In a recent press release, Apple confirmed that iOS 26.2 will be released to all users in December, but it did not provide a specific release date. Keep reading...
Magic Keyboard Touch ID Feature

Apple Releases New Firmware for 140W USB-C Power Adapter, Magic Keyboard and Magic Trackpad

Tuesday November 18, 2025 1:05 pm PST by
Apple today released updated firmware for several accessories, including the 140W USB-C Power Adapter, the Magic Trackpad 2, the Magic Trackpad USB-C, the Magic Keyboard with Touch ID, and the Magic Keyboard with Touch ID and Numeric Keypad. There is no word on what's included in the updated firmware at this time, but it could offer performance improvements and security updates. Accessory...