Browser user agent details leaked: what it means and what to do
Risk level: low. Can you change it: yes. Found in 25 breaches in this directory.
What this data is
A short text string your browser sends to every website, naming the browser, its version, the operating system and often the device type, for example Chrome on Windows or Safari on an iPhone.
The risk on its own
This is low risk, and every site you visit already receives it. It cannot identify you personally because huge numbers of people send the same string. What it can show is an outdated browser or operating system that still carries known security holes.
The risk combined with other data
Stored with your email and IP address, it helps an attacker tailor a trap to your actual setup, such as a fake update page for the exact browser you run. It is also one of several signals used to link your sessions across different leaks. Some fraud checks compare it at login, so an attacker who copies yours looks slightly more like you.
How criminals use it
A phishing page shows a fake browser update for the precise browser and operating system in your record.
An attacker aims an exploit at an old browser version that the string shows you were running.
A criminal logging in to your stolen account sets the same user agent to avoid tripping a new device alert.
What to do now
Update your browser and operating system, and turn on automatic updates so an old version never matches a known weakness.
Never install a browser update from a web page or email. Real updates come from the browser's own settings menu or your device's update screen.
Change the password on the breached account, since user agents are almost always logged beside a login record.
Turn on two-factor authentication so a copied device signature cannot carry an attacker past the login.
Frequently asked questions
Can a user agent identify me?
No. Very many people share the same string. It only becomes identifying when combined with an IP address, screen size and other browser fingerprinting signals.
Should I install an extension that fakes my user agent?
For most people it is not worth it, and an unusual string can make you stand out more. Keeping the browser updated does far more good.
Why did the website store it?
Sites log it for analytics, fraud checks and to show you the list of devices signed in to your account.
Breaches that exposed this data
QuestionPro: 2022-05-21, 22M accounts, Browser user agent details, Email addresses, IP addresses, Survey results
Aptoide: 2020-04-13, 20M accounts, Browser user agent details, Email addresses, IP addresses, Names, Passwords
Prosper: 2025-09-01, 18M accounts, Browser user agent details, Credit status information, Dates of birth, Email addresses, Employment statuses, Government issued IDs
Manchester Airports Group: 2026-08-27, 8.8M accounts, Browser user agent details, Email addresses, Geographic locations, IP addresses, Names, Phone numbers
Genesis Market: 2023-04-05, 8.0M accounts, Browser user agent details, Credit card CVV, Credit cards, Dates of birth, Email addresses, Names
BlankMediaGames: 2018-12-28, 7.6M accounts, Browser user agent details, Email addresses, IP addresses, Passwords, Purchases, Usernames
Wakanim: 2022-08-28, 6.7M accounts, Browser user agent details, Email addresses, IP addresses, Names, Physical addresses, Usernames
Fashion Nexus: 2018-07-09, 1.3M accounts, Browser user agent details, Dates of birth, Email addresses, Genders, IP addresses, Names
Raychat: 2021-01-31, 939K accounts, Browser user agent details, Email addresses, IP addresses, Names, Passwords
ZAP-Hosting: 2021-11-22, 747K accounts, Browser user agent details, Chat logs, Email addresses, IP addresses, Names, Phone numbers
Vedantu: 2019-07-08, 687K accounts, Browser user agent details, Email addresses, Genders, IP addresses, Names, Passwords
GunAuction.com: 2022-12-03, 565K accounts, Browser user agent details, Email addresses, Genders, IP addresses, Partial credit card data, Partial dates of birth
Breach data sourced from Have I Been Pwned, used under CC BY 4.0. Additional breach metadata provided by XposedOrNot. DataExposed is an independent service and is not affiliated with or endorsed by either.