Apple has said it is working to fix a serious bug within its Mac operating system.
The flaw in MacOS High Sierra - the most recent version - makes it possible to gain entry to the machine without a password, and also have access to powerful administrator rights.
“We are working on a software update to address this issue,” Apple said in a statement.
The bug was discovered by Turkish developer Lemi Ergin.
He found that by entering the username "root", leaving the password field blank, and hitting "enter" a few times, he would be granted unrestricted access to the target machine.
Mr Ergin faced criticism for apparently not following responsible disclosure guidelines typically observed by security professionals.
Those guidelines instruct security experts to notify companies of flaws in their products, giving them a reasonable amount of time to fix the flaw before going public.
Mr Ergin did not respond to those claims when asked on Twitter, and the BBC was unable to reach him on Tuesday.
Apple would not confirm or deny whether it knew about the flaw beforehand.
However,
a member of Apple's support forums had posted details of the flaw more than two weeks ago, though the message appears to suggest the vulnerability could be a useful feature for troubleshooting rather than a critical security threat.
