What is CVE-2018-5739?

CVE-2018-5739 is a medium-severity vulnerability in Isc Kea, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 6.5/10. Published 2019-01-16.

How severe is CVE-2018-5739?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Isc Kea

CVE-2018-5739

An extension to hooks capabilities which debuted in Kea 1.4.0 introduced a memory leak for operators who are using certain hooks library facilities. In order to support multiple requests simultaneously, Kea 1.4 added a callout handle store but unfortunately the initial implementation of this store does not properly free memory in every case. Hooks which make use of query4 or query6 parameters in their callouts can leak memory, resulting in the eventual exhaustion of available memory and subsequent failure of the server process. Affects Kea DHCP 1.4.0.

Published 2019-01-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.019 (78.8th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 79th percentile — 78.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.019 · newest: 0.019 · change: 0.000

Affected products

Isc Kea — versions 1.4.0
Isc Kea Dhcp — versions Kea DHCP 1.4.0

Weakness classification (CWE)

CWE-772 — Missing Release of Resource after Effective Lifetime

References

kb.isc.org/docs/aa-01626 (Vendor Advisory)

Frequently asked questions

What is CVE-2018-5739?: CVE-2018-5739 is a medium-severity vulnerability in Isc Kea, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 6.5/10. Published 2019-01-16.
How severe is CVE-2018-5739?: Medium severity. CVSS v3 base score is 6.5 out of 10.