Skip to content
Fencer Vulns
high 7.5

CVE-2022-40188 json

Knot Resolver before 5.5.3 allows remote attackers to cause a denial of service (CPU consumption) because of algorithmic complexity.

published 2022-09-23 4 y ago modified 2026-06-17 4 mo ago also EUVD-2022-43490

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

Knot Resolver before 5.5.3 allows remote attackers to cause a denial of service (CPU consumption) because of algorithmic complexity. During an attack, an authoritative server must return large NS sets or address sets.

Patch / fix

  • nic knot_resolver 5.5.3
  • knot-resolver Debian 14, Debian 13, Debian 12 5.5.3-1

debian advisories DEBIAN-CVE-2022-40188

  • knot-resolver Ubuntu 20.04 LTS 3.2.1-3ubuntu2.1
  • knot-resolver Ubuntu Pro 16.04 LTS 1.0.0~beta3-1ubuntu0.1~esm1
  • knot-resolver Ubuntu Pro 18.04 LTS 2.1.1-1ubuntu0.1~esm2
  • knot-resolver Ubuntu Pro 22.04 LTS 5.4.4-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2022-40188

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • knot-resolver Alpine 3.24, Alpine 3.23, Alpine 3.22 +6 more 5.5.3-r0

alpine advisories ALPINE-CVE-2022-40188

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2022-40188 updated

knot-resolver: CPU-expensive DoS by malicious domains

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
17 mo ago

Exploit prediction

1.95% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Classification

Weakness
  • CWE-407 Inefficient Algorithmic Complexity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.