[USN-5658-2] DHCP vulnerabilities

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Ubuntu Security Notice USN-5658-2
November 07, 2022

isc-dhcp vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM

Summary:

Several security issues were fixed in DHCP.

Software Description:
- isc-dhcp: DHCP server and client

Details:

USN-5658-1 fixed vulnerabilities in DHCP. This update provides
the corresponding updates for Ubuntu 16.04 ESM.

Original advisory details:

It was discovered that DHCP incorrectly handled option reference
counting. A remote attacker could possibly use this issue to cause DHCP
servers to crash, resulting in a denial of service. (CVE-2022-2928)

It was discovered that DHCP incorrectly handled certain memory
operations. A remote attacker could possibly use this issue to cause
DHCP clients and servers to consume resources, leading to a denial of
service. (CVE-2022-2929)

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+esm2
isc-dhcp-server 4.3.3-5ubuntu12.10+esm2

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

References:
https://ubuntu.com/security/notices/USN-5658-2
https://ubuntu.com/security/notices/USN-5658-1
CVE-2022-2928, CVE-2022-2929