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KeaApplication · Ics

CVE-2019-6473

MEDIUM · 6.5 CVSS v3.1 Published 2019-10-16
Fix available
A fix is available. Upgrade to after 1.5.0 or later.
See remediation →
70/100
Remediation priority · Elevated
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An invalid hostname option can trigger an assertion failure in the Kea DHCPv4 server process (kea-dhcp4), causing the server process to exit. Versions affected: 1.4.0 to 1.5.0, 1.6.0-beta1, and 1.6.0-beta2.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

An invalid hostname option in DHCPv4 requests triggers an assertion failure in the Kea DHCPv4 server (kea-dhcp4), causing the server process to exit unexpectedly. This is a denial of service vulnerability resulting from improper handling of malformed hostname options in the DHCP packet processing code.

MitigationUpgrade to Kea DHCP version 1.6.0 or later, which contains the fix. Alternatively, implement network-level filtering to reject DHCP packets with malformed hostname options before they reach the server.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
KeaApplication
Affected:>= 1.4.0, <= 1.5.0= 1.6.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Kea DHCPv4 server is installed
    Run 'kea-dhcp4 -v' or check package manager for kea-dhcp4 package
    Affected if kea-dhcp4 is not installed on the system
  2. Determine installed Kea DHCPv4 version
    Execute 'kea-dhcp4 -v' and note the version number in the output
    Affected if version cannot be determined or command not found
  3. Compare version against affected ranges
    Check if the installed version matches 1.4.0, 1.5.0, or 1.6.0
    Affected if installed version is 1.4.0, 1.5.0, or 1.6.0

User is affected if kea-dhcp4 version is exactly 1.4.0, 1.5.0, or 1.6.0, as these versions contain the vulnerability in handling malformed hostname options in DHCPv4 requests.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 1.5.0
Interim mitigation

Upgrade to Kea DHCP version 1.6.0 or later, which contains the fix. Alternatively, implement network-level filtering to reject DHCP packets with malformed hostname options before they reach the server.

Fix this in Kea Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,750
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2019-6473 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data