USN-3276-1 intended to fix a vulnerability in su. The solution introduced a regression in su signal handling. This update modifies the security fix. We apologize for the inconvenience.
Original advisory details:
Sebastian Krahmer discovered integer overflows in shadow utilities. A local attacker could possibly cause them to crash or potentially gain privileges via crafted input. (CVE-2016-6252)
Tobias StÃ¶ckmann discovered a race condition in su. A local attacker could cause su to send SIGKILL to other processes with root privileges. (CVE-2017-2616)