NetHack: NetHack 3.4.3 privilege escalation

Severity: High
Affected versions: 3.4.3 and earlier
First Patched Version: 3.6.0

Basic Information:
Malicious use of escaping of characters in the configuration file (usually .nethackrc) can be exploited.

This vulnerability affects systems that have NetHack installed suid/sgid and shared systems that allow users to upload their own configuration files.

The NetHack 3.4 series (including 3.4.3) is no longer supported. Users are encouraged to upgrade to the current version as soon as possible. Anyone responsible for maintaining a 3.4 codebase should consider NetHack 3.6.0 commit 612755b.

Additional information related to this advisory, if any, will be made available at

08-Mar-2020 CVE-2020-5253 information referring to the issue in the unsupported 3.4.3 version.
03-Mar-2020 Bug reported by David Mendenhall.
07-Dec-2015 Fix for issue included in the 3.6.0 first public release since 2003.
05-Aug-2011 The NetHack Development Team responded to Matthew Daley via email.
03-Aug-2011 Email received from Matthew Daley by the NetHack Development Team and the admin of admin advising of the issue.

The NetHack Development Team gratefully acknowledges security researcher David Mendenhall for discovering this issue and for responsibly reporting it.

The NetHack Development Team would also like to acknowledge an earlier report of this same issue on August 3, 2011 by Matthew Daley in an email.

Revision History:
03-Jul-2020 Include acknowledgement of earlier report by Matthew Daley.
08-Mar-2020 Initial Version.

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