How severe is CVE-2018-5733?

CVE-2018-5733 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-5733 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 20% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-5733?

CVE-2018-5733 primarily affects Isc Dhcp. In total, 54 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-5733?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-5733 published?

CVE-2018-5733 was published on 2019-01-16 and last updated on 2026-06-17.

CVE-2018-5733

CVE-2018-5733 is a high-severity vulnerability in Isc Dhcp with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 20% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-190.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 20% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Isc Dhcp
Published: 2019-01-16
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2018-5733?: 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.
How severe is CVE-2018-5733?: CVE-2018-5733 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-5733 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 20% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-5733?: CVE-2018-5733 primarily affects Isc Dhcp. In total, 54 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-5733?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-5733 published?: CVE-2018-5733 was published on 2019-01-16 and last updated on 2026-06-17.

References

Affected products (54)

cpe:2.3:a:isc:dhcp:*:*:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:-:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r10:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r10_b1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r10_rc1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r11:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r11_b1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r11_rc1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r11_rc2:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r12:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r12_b1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r12_p1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r13:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r13_b1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r14:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r14_b1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r15:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r2:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r3:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r3_b1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r4:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r5:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r5_b1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r5_rc1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r5_rc2:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r6:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r7:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r8:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r8_b1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r8_rc1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r9:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r9_b1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:r9_rc1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1-esv:rc1:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.1.0:-:*:*:*:*:*:*
cpe:2.3:a:isc:dhcp:4.4.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:*

More vulnerabilities in Isc Dhcp

CVE-2009-0692 — Critical (CVSS 10.0): Stack-based buffer overflow in the script_write_params method in client/dhclient.c in ISC DHCP dhclient 4.1 before…
CVE-2011-2749 — High (CVSS 7.8): The server in ISC DHCP 3.x and 4.x before 4.2.2, 3.1-ESV before 3.1-ESV-R3, and 4.1-ESV before 4.1-ESV-R3 allows remote…
CVE-2011-2748 — High (CVSS 7.8): The server in ISC DHCP 3.x and 4.x before 4.2.2, 3.1-ESV before 3.1-ESV-R3, and 4.1-ESV before 4.1-ESV-R3 allows remote…
CVE-2011-0413 — High (CVSS 7.8): The DHCPv6 server in ISC DHCP 4.0.x and 4.1.x before 4.1.2-P1, 4.0-ESV and 4.1-ESV before 4.1-ESV-R1, and 4.2.x before…
CVE-2018-5732 — High (CVSS 7.5): Failure to properly bounds-check a buffer used for processing DHCP options allows a malicious server (or an entity…
CVE-2017-3144 — High (CVSS 7.5): A vulnerability stemming from failure to properly clean up closed OMAPI connections can lead to exhaustion of the pool…

All CVEs affecting Isc Dhcp →

Other CWE-190 (Integer Overflow or Wraparound) vulnerabilities

CVE-2026-4689 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was…
CVE-2026-24814 — Critical (CVSS 10.0): Integer Overflow or Wraparound vulnerability in swoole swoole-src (thirdparty/hiredis modules). This vulnerability is…
CVE-2025-64721 — Critical (CVSS 10.0): Sandboxie is a sandbox-based isolation software for 32-bit and 64-bit Windows NT-based operating systems. In versions…
CVE-2015-5108 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2015-5097 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2013-2555 — Critical (CVSS 10.0): Integer overflow in Adobe Flash Player before 10.3.183.75 and 11.x before 11.7.700.169 on Windows and Mac OS X, before…

Browse all CWE-190 (Integer Overflow or Wraparound) vulnerabilities →