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CVE Record

CVE-2019-10190: A vulnerability was discovered in DNS resolver component of knot resolver through version 3.2.0 before 4.1....

A vulnerability was discovered in DNS resolver component of knot resolver through version 3.2.0 before 4.1.0 which allows remote attackers to bypass DNSSEC validation for non-existence answer. NXDOMAIN answer would get passed through to the client even if its DNSSEC validation failed, instead of sending a SERVFAIL packet. Caching is not affected by this particular bug but see CVE-2019-10191.

MediumCVSS 5.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Knot Resolver could incorrectly accept a failed DNSSEC proof that a domain does not exist. That can mislead clients relying on the resolver’s DNSSEC validation, but the supplied sources do not show active exploitation. Organizations running affected Knot Resolver versions should upgrade through vendor-supported packages.

Executive priority

Treat this as a moderate DNS integrity issue. It does not have confirmed active exploitation in the supplied sources, but DNSSEC validation failures can undermine trust decisions, so remediate during normal security patch cycles with priority for central resolvers.

Technical view

CVE-2019-10190 affects CZ.NIC knot-resolver from 3.2.0 before 4.1.0. Failed DNSSEC validation for NXDOMAIN answers could still be passed to clients instead of returning SERVFAIL. The CVE notes caching is not affected by this bug and points separately to CVE-2019-10191.

Likely exposure

Exposure is limited to environments running Knot Resolver 3.2.0 through versions before 4.1.0, especially where clients depend on it for DNSSEC validation. Confirm package source and version because distro advisories may backport fixes.

Exploitation context

The source bundle marks KEV as false and provides no cited evidence of active exploitation. The issue is network-reachable in resolver use, but the CVSS vector lists low complexity and low privileges, with limited confidentiality and integrity impact.

Researcher notes

Focus validation on NXDOMAIN DNSSEC failure handling, not cache poisoning for this specific CVE. The CVE description states caching is not affected here, while related caching behavior is associated with CVE-2019-10191.

Mitigation direction

  • Upgrade Knot Resolver to 4.1.0 or a vendor-supported fixed package.
  • Review CZ.NIC, Fedora, Debian, or Red Hat guidance for your installed package line.
  • Prioritize resolvers serving security-sensitive or external client populations.
  • If upgrade is delayed, follow vendor guidance for temporary risk reduction.

Validation and detection

  • Inventory hosts running Knot Resolver and record exact package versions.
  • Confirm whether distro packages include a backported fix for CVE-2019-10190.
  • Verify DNSSEC validation failure handling returns SERVFAIL after remediation.
  • Document whether CVE-2019-10191 also applies to the same resolver fleet.
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

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ATT&CK lookup starting points

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cwe · low confidence lookup

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cve · low confidence lookup

CVE-2019-10190 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.4 (3.0)
Known Exploited
No
Published

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

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
5.4CVSS 3.0MediumCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N2.82.5Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

5.4Medium
CVSS 3.0 vector shape for CVE-2019-10190Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

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
CZ.NICknot-resolverfrom 3.2.0 before 4.1.0Listed
Weakness

CWE details

CWE-20

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