USN-3353-1: Heimdal vulnerability

Ubuntu Security Notice USN-3353-1

14th July, 2017

heimdal vulnerability

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


Heimdal could allow unintended access to network services.

Software description

  • heimdal - Heimdal Kerberos Network Authentication Protocol


Jeffrey Altman, Viktor Dukhovni, and Nicolas Williams discovered
that Heimdal clients incorrectly trusted unauthenticated portions
of Kerberos tickets. A remote attacker could use this to impersonate
trusted network services or perform other attacks.

Update instructions

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

Ubuntu 17.04:
libkrb5-26-heimdal 7.1.0+dfsg-9ubuntu1.1
Ubuntu 16.10:
libkrb5-26-heimdal 1.7~git20150920+dfsg-4ubuntu1.16.10.1
Ubuntu 16.04 LTS:
libkrb5-26-heimdal 1.7~git20150920+dfsg-4ubuntu1.16.04.1
Ubuntu 14.04 LTS:
libkrb5-26-heimdal 1.6~git20131207+dfsg-1ubuntu1.2

To update your system, please follow these instructions:

After a standard system update you need to restart any applications
using Heimdal libraries to make all the necessary changes.