man before 1.5l allows attackers to execute arbitrary code via a malformed man file with improper quotes, which causes the my_xsprintf function to return a string with the value "unsafe," which is then executed as a program via a system call if it is in the search path of the user who runs man.
https://exchange.xforce.ibmcloud.com/vulnerabilities/11512
http://www.redhat.com/support/errata/RHSA-2003-134.html
http://www.redhat.com/support/errata/RHSA-2003-133.html
http://marc.info/?l=bugtraq&m=104802285112752&w=2
http://marc.info/?l=bugtraq&m=104740927915154&w=2
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000620