The logrotation script (/etc/cron.daily/upstart) in the Ubuntu Upstart package before 1.13.2-0ubuntu9, as used in Ubuntu Vivid 15.04, allows local users to execute arbitrary commands and gain privileges via a crafted file in /run/user/*/upstart/sessions/.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.007
EPSS Ranking 70.2%