CVE-2018-5733 A malicious client can overflow a reference counter in ISC dhcpd

What is CVE-2018-5733?

CVE-2018-5733 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 16 Jan 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A malicious client which is allowed to send very large amounts of traffic (billions of packets) to a DHCP server can eventually overflow a 32-bit reference counter, potentially causing dhcpd to crash. Affects ISC DHCP 4.1.0 -> 4.1-ESV-R15, 4.2.0 -> 4.2.8, 4.3.0 -> 4.3.6, 4.4.0.

Weakness: CWE-190

Which versions are affected by CVE-2018-5733?

It affects 8 products.

Products include Canonical Ubuntu Linux, Debian Debian Linux, Isc Dhcp, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus and 2 more.

How do I fix CVE-2018-5733?

Upgrade to a fixed version.

Is CVE-2018-5733 being exploited?

There is no known exploitation of CVE-2018-5733 in the wild and no public exploit code.

Other vulnerabilities in Canonical Ubuntu Linux

• CVE-2020-11651 SaltStack Salt Authentication Bypass Exploited Critical 9.8
• CVE-2020-7247 OpenSMTPD Remote Code Execution Exploited Critical 9.8
• CVE-2019-16928 Exim Out-of-bounds Write Exploited Critical 9.8
• CVE-2018-6789 Exim Buffer Overflow Exploited Critical 9.8
• CVE-2015-2590 Oracle Java SE and Java SE Embedded Remote Code Execution Exploited Critical 9.8

All Canonical Ubuntu Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2018-5733, DEBIAN-CVE-2018-5733, GHSA-6f7q-j62j-5545, UBUNTU-CVE-2018-5733.