CVE-2019-6474 | A packet containing a malformed DUID can cause the kea-dhcp6 server to terminate

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 1.6.0-beta2

Published: 2019-10-16 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-6474 is rated Low Risk (39.4/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.71%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2019-6474

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 2026-06-23 1.13% 0.71% -0.42%
2 2026-06-15 1.59% 1.13% -0.47%
3 2025-11-21 — 1.59% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-6474

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.7 3.1 MEDIUM
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
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.
 2.1 3.6 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
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.
 2.8 3.6 [email protected]
6.1 2.0 MEDIUM
AV:A/AC:L/Au:N/C:N/I:N/A:C Click to expand
Access vector (AV:A)
Requires access to an adjacent network segment.
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:C)
Complete availability impact.
 6.5 6.9 [email protected]

Weakness enumeration for CVE-2019-6474

OS Trackers for CVE-2019-6474

vendor priority summary link
alpine medium CVE-2019-6474: 1 source package rows (kea); 8 state rows across 8 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-community, edge-main); fixed 8, open 0. https://security.alpinelinux.org/vuln/CVE-2019-6474
debian not yet assigned CVE-2019-6474 not yet assigned priority: Debian including 1 source packages (isc-kea), 4 status rows across 4 suites (bookworm, forky, sid, trixie): resolved 4. https://security-tracker.debian.org/tracker/CVE-2019-6474
ubuntu medium CVE-2019-6474 medium priority: Ubuntu including 1 source packages (isc-kea), 17 status rows across 17 suites (bionic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 8, ignored 7, DNE 1, released 1. https://ubuntu.com/security/CVE-2019-6474

Affected software / configurations for CVE-2019-6474

Vendor Product Version Raw CPE
isc kea >= 1.4.0, <= 1.5.0 cpe:2.3:a:isc:kea:*:*:*:*:*:*:*:*
isc kea 1.6.0 cpe:2.3:a:isc:kea:1.6.0:beta1:*:*:*:*:*:*
isc kea 1.6.0 cpe:2.3:a:isc:kea:1.6.0:beta2:*:*:*:*:*:*

References for CVE-2019-6474

URL Tags
https://kb.isc.org/docs/cve-2019-6474 Vendor Advisory
cvelogic Threat Intelligence