A bug in Firefox which allows different users in Win XP to see each other’s visited sites prompted a woman to leave her fiance of 5 years after discovering he’s been visiting online dating sites.

Steps to reproduce bug.

Steps to Reproduce:
1. Create 2 unique user accounts (for steps sake, let’s call the two accounts Joe and Mary) in Windows XP Home.
2. Logout and sign-in under Joe.
3. Open Firefox and go to an e-mail site or to jdate.com or wherever.
4. Attempt to log-in to the site so that Firefox will ask whether or not you want your password saved.
5. Choose not to save the password.
6. After successfully logging in and having selected the “never save password” option, logout.
7. Log-in as Mary and open Firefox.
8. Browse, browse, browse… but you don’t really have to. Just go to “View Saved Passwords,” click on the tab that will show you sites to never save passwords for, and you’ll see whatever painful site Joe denied to save a
password for.
9. Break-up with fiancé.

Read the bugzilla report here.