NetHack AUTOCOMPLETE configuration file option is subject to a buffer overflow

In NetHack before 3.6.5, an invalid extended command in value for the AUTOCOMPLETE configuration file option can cause a buffer overflow resulting in a crash or remote code execution/privilege escalation. This vulnerability affects systems that have NetHack installed suid/sgid and shared systems that allow users to upload their own configuration files. Users should upgrade to NetHack 3.6.5.