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CVE Record

CVE-2022-40188: Knot Resolver before 5.5.3 allows remote attackers to cause a denial of service (CPU consumption) because o...

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.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2022-40188 is a denial-of-service flaw in Knot Resolver before 5.5.3. A remote attacker can drive high CPU use by causing the resolver to process unusually large DNS delegation or address data, potentially degrading DNS resolution for dependent users and services.

Executive priority

Prioritize remediation for internet-facing or business-critical DNS resolvers. This is high-impact availability risk, not a confidentiality breach, but DNS outages can cascade into application downtime and incident response load.

Technical view

The issue is CWE-407 algorithmic complexity in Knot Resolver. The CVE states remote attackers can cause CPU-consumption DoS when an authoritative server returns large NS sets or address sets. CVSS 3.1 is 7.5, network-accessible, no authentication or user interaction, availability impact only.

Likely exposure

Exposure is limited to environments running Knot Resolver before 5.5.3, including older distro packages referenced by Fedora and Debian LTS advisories. Systems not using Knot Resolver are not indicated as affected by the provided sources.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation evidence. Exploitation requires influencing resolver traffic so it receives large NS or address sets from an authoritative server, leading to excessive CPU use rather than data theft or code execution.

Researcher notes

Evidence is concise but consistent: CVE metadata, upstream GitLab reference, Fedora advisories, and Debian LTS advisory. The provided affected CPE data is not populated, so validation should rely on product inventory and package version checks.

Mitigation direction

  • Upgrade Knot Resolver to 5.5.3 or a vendor-supported fixed package.
  • Apply relevant Fedora or Debian LTS security updates where those packages are used.
  • Check upstream Knot Resolver guidance for any newer maintenance recommendations.
  • Monitor resolver CPU saturation and availability until updates are confirmed.

Validation and detection

  • Inventory recursive DNS resolvers and identify any Knot Resolver deployments.
  • Confirm installed Knot Resolver versions are 5.5.3 or vendor-fixed builds.
  • Review Fedora or Debian package advisory status for managed hosts.
  • Check DNS service metrics for unexplained CPU spikes or resolution latency.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-407: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2022-40188 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2022-40188Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

CWE-407

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-407 · source CWE mapping

Inefficient Algorithmic Complexity

Inefficient Algorithmic Complexity represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs