The daily mandb cleanup job in Man-db before 2.7.6.1-1 as packaged in Ubuntu and Debian allows local users with access to the man account to gain privileges via vectors involving insecure chown use.
https://security.gentoo.org/glsa/201707-12
https://bugs.launchpad.net/ubuntu/+source/man-db/+bug/1482786
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=840357
http://www.securityfocus.com/bid/79723
http://www.openwall.com/lists/oss-security/2015/12/14/11
http://people.canonical.com/~ubuntu-security/cve/2015/CVE-2015-1336.html