Nano: running `chmod` and `chown` on the filename allows malicious user to replace the emergency file with a malicious symlink to a root-owned file

A vulnerability was found in GNU Nano that allows a possible privilege escalation through an insecure temporary file. If Nano is killed while editing, a file it saves to an emergency file with the permissions of the running user provides a window of opportunity for attackers to escalate privileges through a malicious symlink.