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CVE Record

CVE-2019-10191: A vulnerability was discovered in DNS resolver of knot resolver before version 4.1.0 which allows remote at...

A vulnerability was discovered in DNS resolver of knot resolver before version 4.1.0 which allows remote attackers to downgrade DNSSEC-secure domains to DNSSEC-insecure state, opening possibility of domain hijack using attacks against insecure DNS protocol.

MediumCVSS 6.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2019-10191 affects Knot Resolver before 4.1.0. An attacker could make a DNSSEC-protected domain appear insecure, reducing trust in DNS answers and creating a path toward domain hijack through insecure DNS behavior.

Executive priority

Treat as a scheduled remediation for DNS infrastructure. It is not sourced as actively exploited, but DNS trust failures can affect authentication, routing, and service integrity.

Technical view

The issue is a CWE-20 input-validation weakness in CZ.NIC knot-resolver before 4.1.0. Public CVE text says remote attackers can downgrade DNSSEC-secure domains to DNSSEC-insecure state. CVSS 3.0 is 6.3, with low attack complexity and limited confidentiality, integrity, and availability impact.

Likely exposure

Exposure is limited to environments running CZ.NIC Knot Resolver versions before 4.1.0, especially recursive DNS resolver infrastructure relying on DNSSEC validation.

Exploitation context

The provided sources do not show CISA KEV listing or confirmed active exploitation. The risk is meaningful because DNSSEC downgrade can undermine resolver trust, but evidence here does not support calling it exploited in the wild.

Researcher notes

Evidence identifies the affected product and fixed upstream version but provides limited implementation detail. Avoid assuming affected forks, exploit availability, or compensating controls beyond vendor and distribution guidance.

Mitigation direction

  • Upgrade Knot Resolver to 4.1.0 or a vendor-fixed package.
  • Apply relevant Fedora, Debian, Red Hat, or distribution security updates.
  • Prioritize resolvers serving production, internet-facing, or sensitive internal clients.
  • Check vendor guidance for unsupported or custom-built deployments.

Validation and detection

  • Inventory systems running knot-resolver and record package versions.
  • Confirm all deployments are version 4.1.0 or vendor-patched.
  • Review resolver configuration for DNSSEC validation dependency.
  • Check distribution advisories for matching fixed package status.
Prepared
Confidence
high
Sources
6

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-20: Exact CWE lookup

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cve · low confidence lookup

CVE-2019-10191 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
Medium
CVSS
6.3 (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:L

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
6.3CVSS 3.0MediumCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L2.83.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

6.3Medium
CVSS 3.0 vector shape for CVE-2019-10191Attack 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:L

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-resolverall 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.