USN-4969-3: DHCP regression

Releases

• Ubuntu 21.04

Packages

• isc-dhcp - DHCP server and client

Details

USN-4969-1 fixed a vulnerability in DHCP. The package for Ubuntu 21.04
introduced a regression causing it to reject certain valid configuration
files. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Jon Franklin and Pawel Wieczorkiewicz discovered that DHCP incorrectly
handled lease file parsing. A remote attacker could possibly use this issue
to cause DHCP to crash, resulting in a denial of service.

Update instructions

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

Ubuntu 21.04

• isc-dhcp-client - 4.4.1-2.2ubuntu6.2
• isc-dhcp-server - 4.4.1-2.2ubuntu6.2

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

References

• https://launchpad.net/bugs/1930917