Please help me.
I have a big problem, everyone can login to my magento admin panel with any password.
When use the username admin and any password everybody can login.
For example i use password 12345 i can login and i use a another like 789454 i can login.
I have never seen this?
This sounds serious. Are you sure you are logged completely out of the admin area before you try these other passwords? (Try clearing cookies after logging out to be sure.) Are you using any extensions or custom code on Magento installation? When did the problem first start happening? Are you noticing any other evidence of tampering on your site?