CVE-2018-5732 A specially constructed response from a malicious server can cause a buffer overflow in dhclient

High 7.5 Published 9 Oct 2019 Updated 16 Sep 2024

A malicious DHCP server can cause a buffer overflow and crash in the ISC DHCP client by sending specially crafted options.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2018-5732?

CVE-2018-5732 is a high-severity memory corruption vulnerability in ISC DHCP, published on 9 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Failure to properly bounds-check a buffer used for processing DHCP options allows a malicious server (or an entity masquerading as a server) to cause a buffer overflow (and resulting crash) in dhclient by sending a response containing a specially constructed options section. Affects ISC DHCP versions 4.1.0 -> 4.1-ESV-R15, 4.2.0 -> 4.2.8, 4.3.0 -> 4.3.6, 4.4.0

Weakness: CWE-119

Which versions are affected by CVE-2018-5732?

It affects 1 product.

Products include Isc Dhcp.

How do I fix CVE-2018-5732?

Upgrade to a fixed version.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2018-5732 being exploited?

There is no known exploitation of CVE-2018-5732 in the wild and no public exploit code.

Sources

Also known as ALPINE-CVE-2018-5732, DEBIAN-CVE-2018-5732, GHSA-j4cm-vph7-f7qg, UBUNTU-CVE-2018-5732.