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USN-3673-1: Unbound vulnerability

7 June 2018

A security issue was fixed in Unbound.



  • unbound - validating, recursive, caching DNS resolver


Ralph Dolmans and Karst Koymans discovered that Unbound did not properly
handle certain NSEC records. An attacker could use this to to prove the
non-existence (NXDOMAIN answer) of an existing wildcard record, or trick
Unbound into accepting a NODATA proof.

Update instructions

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

Ubuntu 18.04
Ubuntu 17.10
Ubuntu 16.04
Ubuntu 14.04

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