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USN-5034-1: c-ares vulnerability

10 August 2021

c-ares could be made to return wrong domains.



  • c-ares - library for asynchronous name resolution


Philipp Jeitner and Haya Shulman discovered that c-ares incorrectly
validated certain hostnames returned by DNS servers. A remote attacker
could possibly use this issue to perform Domain Hijacking attacks.

Update instructions

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

Ubuntu 21.04
Ubuntu 20.04
Ubuntu 18.04

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


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