TYPO3 Core

This is really strange.
Do you have any special extensions running?

I have some extensions running, but none, which would change anything with user authentication...

Just stumbled upon this one today and there is a conceptional problem.

The \TYPO3\CMS\Sv\AbstractAuthenticationService that is used for all authentication services provides a writelog() method. This method will use the writelog() method in the parent \TYPO3\CMS\Core\Authentication\AbstractUserAuthentication object, if the class variable $writeAttemptLog is TRUE.

So basically an authentication service is supposed to use the writelog() method when a login attempt was successful or not.

This is working correctly for successful logins, because then the value in $this->user['uid'] is filled. But for failed logins there will always be an error, because $this->user only contains a string.

This can be fixed quite simple by checking if $this->user is an array.

Patch set 2 for branch master has been pushed to the review server.
It is available at https://review.typo3.org/23116

Patch set 3 for branch master has been pushed to the review server.
It is available at https://review.typo3.org/23116

Patch set 1 for branch TYPO3_6-1 has been pushed to the review server.
It is available at https://review.typo3.org/23916

Patch set 1 for branch TYPO3_6-0 has been pushed to the review server.
It is available at https://review.typo3.org/23917