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Vulnerability record · CVE-2019-19331 · published 16 December 2019

CVE-2019-19331: Nic knot resolver improper resource shutdown vulnerability

Nic · Knot Resolver

knot-resolver before version 4.3.0 is vulnerable to denial of service through high CPU utilization. DNS replies with very many resource records might be processed very inefficiently, in extreme cases taking even several CPU seconds for each such uncached message. For example, a few thousand A records can be squashed into one DNS message (limit is 64kB).

7.5 CVSS 3.1 High EPSS 2.2% · top 18.4% CWE-407 · CWE-407CWE-404 · Improper resource shutdown
7.5CVSS 3.1 base score, v2 5.0
2.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
6References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

knot-resolver before version 4.3.0 is vulnerable to denial of service through high CPU utilization. DNS replies with very many resource records might be processed very inefficiently, in extreme cases taking even several CPU seconds for each such uncached message. For example, a few thousand A records can be squashed into one DNS message (limit is 64kB).

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-19331 ExploitIssue TrackingPatch
https://lists.debian.org/debian-lts-announce/2024/04/msg00017.html
https://www.knot-resolver.cz/2019-12-04-knot-resolver-4.3.0.html Release NotesVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-19331 ExploitIssue TrackingPatch
https://lists.debian.org/debian-lts-announce/2024/04/msg00017.html
https://www.knot-resolver.cz/2019-12-04-knot-resolver-4.3.0.html Release NotesVendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2019-19331), CISA KEV, FIRST EPSS (scores of 2026-10-02). This page is refreshed as NVD updates the record.