CVE-2019-6474: A missing check on incoming client requests can be exploited to cause a situation where the Kea server's lease

Routine

MEDIUM 5.7UPGRADE

CVE-2019-6474 is a medium-severity flaw (CVSS 5.7) affecting kea. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A missing check on incoming client requests can be exploited to cause a situation where the Kea server's lease storage contains leases which are rejected as invalid when the server tries to load leases from storage on restart. If the number of such leases exceeds a hard-coded limit in the Kea code, a server trying to restart will conclude that there is a problem with its lease store and give up. Versions affected: 1.4.0 to 1.5.0, 1.6.0-beta1, and

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.7 (Medium)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.7% (top 46%)
CISA exploited list	No
Weakness	CWE-772
Published	2019-10-16
Last modified	2026-06-17

Publisher (CNA): Internet Systems Consortium (ISC) · Vendor: isc

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2019-10-16 18:15 UTCPublished CVE record published
2026-06-17 02:39 UTCUpdated Record last modified

isc kea UPGRADE

Affected: >= 1.4.0 and <= 1.5.0 · 1.6.0 beta1 · 1.6.0 beta2

Fixed in: newer than 1.5.0

Safe to downgrade to: a release before 1.4.0

1. Check installed version

apt-cache policy kea || rpm -q kea || kea --version

2. UPGRADE to newer than 1.5.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade kea

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade kea

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.4.0 (Debian / Ubuntu)

apt-cache madison kea sudo apt install kea=<VERSION_BEFORE_1.4.0> sudo apt-mark hold kea

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list kea sudo dnf downgrade kea-<VERSION_BEFORE_1.4.0> sudo dnf versionlock add kea

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2019-6474?

kea: upgrade to newer than 1.5.0. Exact commands for each OS are on this page.

Is CVE-2019-6474 being exploited?

CVE-2019-6474 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2019-6474 affect?

CVE-2019-6474 affects kea. Severity is medium (CVSS 5.7). A missing check on incoming client requests can be exploited to cause a situation where the Kea server's lease storage contains leases which are rejected as invalid when the server tries to load leases from storage on restart. If the number

How urgent is CVE-2019-6474?

Priority 33/100. No elevated risk signals yet.

Related CVEs

CVE-2019-6473 MEDIUM 6.5 UPGRADE An invalid hostname option can trigger an assertion failure in the Kea DHCPv4 server process (kea-dhcp4), caus
CVE-2019-6472 MEDIUM 6.5 UPGRADE A packet containing a malformed DUID can cause the Kea DHCPv6 server process (kea-dhcp6) to exit due to an ass
CVE-2018-5739 MEDIUM 6.5 DOWNGRADE An extension to hooks capabilities which debuted in Kea 1.4.0 introduced a memory leak for operators who are u

References

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