Ubuntu Security Notice USN-768-1 – Stephane Chazelas discovered that Apport did not safely remove files from its crash report directory. If Apport had been enabled at some point, a local attacker could remove arbitrary files from the system.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/77136/USN-768-1.txt
Source: https://packetstormsecurity.com/files/77136/Ubuntu-Security-Notice-768-1.html