Race condition in GNU nano before 2.2.4, when run by root to edit a file that is not owned by root, allows local user-assisted attackers to change the ownership of arbitrary files via vectors related to the creation of backup files.

GNU nano before 2.2.4 does not verify whether a file has been changed before it is overwritten in a file-save operation, which allows local user-assisted attackers to overwrite arbitrary files via a symlink attack on an attacker-owned file that is being edited by the victim.