CSRF is an attack that forces an end user to execute unwanted actions on a web application in which they're currently authenticated. An attacker may trick the user into clicking a malicious link or submitting a forged form that performs an action on the user's behalf, such as changing their password or transferring funds. If the user has several tabs open in the browser, they may not notice the CSRF request or the resulting change in their account. Updating the browser may have cleared the user's cache or cookies, preventing them from logging in to their account after the CSRF attack.