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TI-2019-13943 Aliases CVE-2019-19331GHSA-9f7v-8m4p-pv76

knot-resolver before version 4.3.0 is vulnerable to denial of service through high CPU…

Priority LOW 37CWE-407Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-407.

Summary

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).

Why it matters now

EPSS 0.02107 81st percentileScored 2026-11-08
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
CZ.NICknot-resolver4.3.0—No fix listedCNA
  • knot-resolver VendorCZ.NIC Affected 4.3.0 Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:nic:knot_resolver:*:*:*:*:*:*:*:*before 4.3.0VulnerableCZ.NIC
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*10.0VulnerableDebian
  • cpe:2.3:a:nic:knot_resolver:*:*:*:*:*:*:*:* Versions before 4.3.0 Vulnerable ·CZ.NIC
  • cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2019-19331
  2. 2026-10-03 Alias added: GHSA-9f7v-8m4p-pv76

References

Exploit 1

Advisory 1

Other 1

  • TI-2023-27571 Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related… CVSS 3.1HIGH 7.5
  • TI-2020-10072 Knot Resolver before 5.1.1 allows traffic amplification via a crafted DNS answer from an… CVSS 3.1HIGH 7.5
  • TI-2022-19055 Knot Resolver before 5.5.3 allows remote attackers to cause a denial of service (CPU… CVSS 3.1HIGH 7.5
  • TI-2023-24930 Knot Resolver before 5.7.0 performs many TCP reconnections upon receiving certain nonsensical responses from servers. CVSS 3.1HIGH 7.5
  • TI-2023-11416 Knot Resolver before 5.6.0 enables attackers to consume its resources, launching… CVSS 3.1HIGH 7.5
  • TI-2019-07512 Improper input validation in CZ.NIC knot-resolver CVSS 3.1HIGH 7.5
See all 13 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences