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No exploitation reportedFix available

CVE-2019-19331

No exploitation reported by the sources we read.

  • Published2019-12-16
  • WeaknessCWE-404 · CWE-407

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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).

Timeline

dates in UTC
  1. 2019-12-1616:15CVE publishedNVD

Versions per branch

NVD
Debian debian linux
BranchAffectedFixed in
10.0= 10.0no fix published
Nic knot resolver
BranchAffectedFixed in
4.3< 4.3.04.3.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • knot-resolverUbuntu:Pro:18.04:LTSall versions · no fixed version listed
  • knot-resolverUbuntu:Pro:16.04:LTSall versions · no fixed version listed
  • knot-resolverUbuntu:20.04:LTSall versions · fixed in 3.2.1-3ubuntu2.2
  • knot-resolverDebian:14all versions · fixed in 5.0.1-1
  • knot-resolverDebian:13all versions · fixed in 5.0.1-1
  • knot-resolverDebian:12all versions · fixed in 5.0.1-1
  • knot-resolverDebian:10all versions · fixed in 3.2.1-3+deb10u2
  • knot-resolverCleanStartall versions · fixed in 4.3.0-r0

14 more package ranges on OSV.dev

Vendor advisories

  • CVE-2019-19331 Red Hat Product Security

    knot-resolver: DNS packets taking few seconds to process with full CPU utilization leads to DoS

Full record on NVD

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.5read 2026-10-23
  • CNACVSS 3.07.5known since 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • CNAweakness (CWE)CWE-407known since 2026-10-23
  • NVDweakness (CWE)CWE-404read 2026-10-23
  • FIRST EPSSEPSS score2.1 %2026-11-08
  • OSVaffected packages—
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2019-12-16
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-9f7v-8m4p-pv76

Frequently asked questions

What is CVE-2019-19331?

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).

Is CVE-2019-19331 actively exploited?

Active exploitation of CVE-2019-19331 has not been confirmed. Its EPSS score was 2.1% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-19331?

CVE-2019-19331 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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