Ubuntu Security Notice 4969-2 - USN-4969-1 fixed a vulnerability in DHCP. This update provides the corresponding update for Ubuntu 14.04 ESM and 16.04 ESM. 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. Various other issues were also addressed.
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Ubuntu Security Notice USN-4969-2
May 27, 2021
isc-dhcp vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM
Summary:
DHCP could be made to crash if it received specially crafted network
traffic.
Software Description:
- isc-dhcp: DHCP server and client
Details:
USN-4969-1 fixed a vulnerability in DHCP. This update provides
the corresponding update for Ubuntu 14.04 ESM and 16.04 ESM.
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 16.04 ESM:
isc-dhcp-client 4.3.3-5ubuntu12.10+esm1
isc-dhcp-server 4.3.3-5ubuntu12.10+esm1
Ubuntu 14.04 ESM:
isc-dhcp-client 4.2.4-7ubuntu12.13+esm1
isc-dhcp-server 4.2.4-7ubuntu12.13+esm1
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-4969-2
https://ubuntu.com/security/notices/USN-4969-1
CVE-2021-25217