If someone got hold of a user's "remember me" cookie, they could keep using it to log in as that user for a long time. The user logging out or resetting their password didn't cancel it.

See the Laravel 4.1.26 upgrade notes.

Who is affected

Apps on laravel/framework 4.0 or 4.1 before 4.1.26 that offer Laravel's "remember me" login option. The attacker first needs a copy of the cookie. Apps that don't use "remember me" aren't affected.

What to do

Update to 4.1.26. You also need to add a remember_token column to your users table, or whichever table holds your users. The upgrade notes explain the change.

After the update, Laravel gives each user a fresh token every time they log in and replaces it when they log out. Logging out then makes a stolen remember-me cookie useless.

Laravel 4 stopped getting fixes long ago, so plan a move to a supported version.