USN-3276-2: shadow regression

Ubuntu Security Notice USN-3276-2

16th May, 2017

shadow regression

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 17.04
  • Ubuntu 16.10
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS


USN-3276-1 introduced a regression in su.

Software description

  • shadow - system login tools


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 Stöckmann discovered a race condition in su. A local
attacker could cause su to send SIGKILL to other processes with
root privileges. (CVE-2017-2616)

Update instructions

The problem can be corrected by updating your system to the following package version:

Ubuntu 17.04:
passwd 1:4.2-3.2ubuntu1.17.04.2
login 1:4.2-3.2ubuntu1.17.04.2
uidmap 1:4.2-3.2ubuntu1.17.04.2
Ubuntu 16.10:
passwd 1:4.2-3.2ubuntu1.16.10.2
login 1:4.2-3.2ubuntu1.16.10.2
uidmap 1:4.2-3.2ubuntu1.16.10.2
Ubuntu 16.04 LTS:
passwd 1:4.2-3.1ubuntu5.3
login 1:4.2-3.1ubuntu5.3
uidmap 1:4.2-3.1ubuntu5.3
Ubuntu 14.04 LTS:
passwd 1:
login 1:
uidmap 1:

To update your system, please follow these instructions:

In general, a standard system update will make all the necessary changes.


LP: 1690820