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

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

Published: 2019-10-09 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-5732 is rated Moderate Risk (58.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.52%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2018-5732

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-09 3.64% 2.52% -1.12%
2 2026-04-13 2.06% 3.64% +1.58%
3 2026-02-18 — 2.06% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-5732

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2018-5732

OS Trackers for CVE-2018-5732

vendor priority summary link
alpine high CVE-2018-5732: 1 source package rows (dhcp); 8 state rows across 8 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, edge-main); fixed 8, open 0. https://security.alpinelinux.org/vuln/CVE-2018-5732
debian not yet assigned CVE-2018-5732 not yet assigned priority: Debian including 1 source packages (isc-dhcp), 4 status rows across 4 suites (bookworm, bullseye, sid, trixie): resolved 4. https://security-tracker.debian.org/tracker/CVE-2018-5732
gentoo normal CVE-2018-5732: 1 GLSA(s) (201804-05), 1 atom(s) (net-misc/dhcp); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2018-5732
redhat high — https://access.redhat.com/security/cve/CVE-2018-5732
suse high — https://www.suse.com/security/cve/CVE-2018-5732/
ubuntu medium CVE-2018-5732 medium priority: Ubuntu including 1 source packages (isc-dhcp), 5 status rows across 5 suites (artful, bionic, trusty, upstream, xenial): released 4, needs-triage 1. https://ubuntu.com/security/CVE-2018-5732

Affected software / configurations for CVE-2018-5732

Vendor Product Version Raw CPE
isc dhcp >= 4.1.0, <= 4.1.2 cpe:2.3:a:isc:dhcp:*:*:*:*:*:*:*:*
isc dhcp >= 4.2.0, < 4.2.8 cpe:2.3:a:isc:dhcp:*:*:*:*:*:*:*:*
isc dhcp >= 4.3.0, < 4.3.6 cpe:2.3:a:isc:dhcp:*:*:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:-:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r10:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r10b1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r10rc1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r11:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r11b1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r11rc1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r11rc2:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r12:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r12-p1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r12b1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r13:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r13b1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r14:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r14b1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r15:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r2:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r3:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r3b1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r4:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r5:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r5b1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r5rc1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r5rc2:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r6:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r7:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r8:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r8b1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r8rc1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r9:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r9b1:*:*:*:*:*:*
isc dhcp 4.1-esv cpe:2.3:a:isc:dhcp:4.1-esv:r9rc1:*:*:*:*:*:*
isc dhcp 4.1.2 cpe:2.3:a:isc:dhcp:4.1.2:p1:*:*:*:*:*:*
isc dhcp 4.4.0 cpe:2.3:a:isc:dhcp:4.4.0:*:*:*:*:*:*:*

References for CVE-2018-5732

URL Tags
https://kb.isc.org/docs/aa-01565 Vendor Advisory
cvelogic Threat Intelligence