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

Published Feb 28, 2018
·
Updated

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.

Versions of DHCP affected: 4.1.0 -> 4.1-ESV-R15, 4.2.0 -> 4.2.8, 4.3.0 -> 4.3.6, 4.4.0

Other sources

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.

Launchpad

Affected Software

59 affected componentsFixes available
redhat/dhcp<4.1
4.1
redhat/dhcp<4.3.6
4.3.6
redhat/dhcp<4.4.1
4.4.1
ISC DHCP>=4.2.0<=4.2.8
ISC DHCP>=4.3.0<=4.3.6
ISC DHCP=4.1-esv
ISC DHCP=4.1-esv-r1
ISC DHCP=4.1-esv-r10
ISC DHCP=4.1-esv-r10_b1
ISC DHCP=4.1-esv-r10_rc1
ISC DHCP=4.1-esv-r11
ISC DHCP=4.1-esv-r11_b1
ISC DHCP=4.1-esv-r11_rc1
ISC DHCP=4.1-esv-r11_rc2
ISC DHCP=4.1-esv-r12
ISC DHCP=4.1-esv-r12_b1
ISC DHCP=4.1-esv-r12_p1
ISC DHCP=4.1-esv-r13
ISC DHCP=4.1-esv-r13_b1
ISC DHCP=4.1-esv-r14
ISC DHCP=4.1-esv-r14_b1
ISC DHCP=4.1-esv-r15
ISC DHCP=4.1-esv-r2
ISC DHCP=4.1-esv-r3
ISC DHCP=4.1-esv-r3_b1
ISC DHCP=4.1-esv-r4
ISC DHCP=4.1-esv-r5
ISC DHCP=4.1-esv-r5_b1
ISC DHCP=4.1-esv-r5_rc1
ISC DHCP=4.1-esv-r5_rc2
ISC DHCP=4.1-esv-r6
ISC DHCP=4.1-esv-r7
ISC DHCP=4.1-esv-r8
ISC DHCP=4.1-esv-r8_b1
ISC DHCP=4.1-esv-r8_rc1
ISC DHCP=4.1-esv-r9
ISC DHCP=4.1-esv-r9_b1
ISC DHCP=4.1-esv-r9_rc1
ISC DHCP=4.1-esv-rc1
ISC DHCP=4.1.0
ISC DHCP=4.4.0
redhat Enterprise Linux Desktop=6.0
redhat Enterprise Linux Desktop=7.0
redhat Enterprise Linux Server=6.0
redhat Enterprise Linux Server=7.0
redhat Enterprise Linux Server Aus=7.4
redhat Enterprise Linux Server Aus=7.6
redhat Enterprise Linux Server Eus=7.4
redhat Enterprise Linux Server Eus=7.5
redhat Enterprise Linux Server Eus=7.6
redhat Enterprise Linux Workstation=6.0
redhat Enterprise Linux Workstation=7.0
Canonical Ubuntu Linux=14.04
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=17.10
Debian Debian Linux=7.0
Debian Debian Linux=8.0
Debian Debian Linux=9.0
debian/isc-dhcp
4.4.1-2.3+deb11u24.4.1-2.3+deb11u14.4.3-P1-24.4.3-P1-8

Remediation

Information

Upgrade to the patched release most closely related to your current version of DHCP. DHCP 4.1-ESV-R15-P1 DHCP 4.3.6-P1 DHCP 4.4.1

Event History

Feb 28, 2018
Data Sourced
08:42 PM
SeverityAffected Software
Jan 16, 2019
CVE Published
via MITRE·08:00 PM
Data Sourced
via MITRE·08:00 PM
RemedyDescriptionSeverityWeakness
Jan 11, 2024
Data Sourced
via Launchpad·11:08 PM
Description
Feb 20, 2026
Data Sourced
via Ubuntu·04:51 PM
RemedyDescriptionSeverityAffected Software
Data Sourced
via Debian·04:51 PM
DescriptionAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2018-5733?

CVE-2018-5733 is considered a high severity vulnerability as it can lead to the crash of a DHCP server.

2

How do I fix CVE-2018-5733?

To fix CVE-2018-5733, upgrade the DHCP server software to versions 4.1.1 or later, or apply the necessary patches provided by your distribution.

3

What software is affected by CVE-2018-5733?

CVE-2018-5733 affects ISC DHCP versions 4.1.0 through 4.2.8 as well as specific versions up to 4.3.6 and 4.4.1.

4

What could an attacker do with CVE-2018-5733?

An attacker could exploit CVE-2018-5733 by sending a large volume of traffic to overwhelm the DHCP server, potentially leading to service disruptions.

5

Is CVE-2018-5733 a remote code execution vulnerability?

No, CVE-2018-5733 does not involve remote code execution; it can cause a denial of service by crashing the DHCP service instead.

Contact

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