Knot ResolverApplication · Nic

CVE-2018-1110

HIGH · 7.5 CVSS v3.1 Published 2021-03-30
Fix available
A fix is available. Upgrade to 2.3.0 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable 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
A flaw was found in knot-resolver before version 2.3.0. Malformed DNS messages may cause denial of service.

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 · moderate confidence

A denial-of-service vulnerability exists in knot-resolver before version 2.3.0 where malformed DNS messages can trigger a service crash. The vulnerability stems from insufficient validation or improper handling of crafted DNS packets during processing.

MitigationUpdate knot-resolver to version 2.3.0 or later to patch the vulnerability. Additionally, consider implementing DNS traffic filtering or rate limiting at network boundaries as a defense-in-depth measure.

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
Knot ResolverApplication
Affected:< 2.3.0

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/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. Check if knot-resolver is installed
    Look for the knot-resolver service or binary. On Linux systems, check for /usr/sbin/kresd, or run 'which kresd' or 'systemctl list-units | grep knot'. Also check for package installations via 'dpkg -l | grep knot-resolver' or 'rpm -qa | grep knot-resolver'.
    Affected if knot-resolver is not installed on the system
  2. Determine the installed version of knot-resolver
    Run 'kresd --version' or check the package version: 'dpkg -l knot-resolver' (Debian/Ubuntu) or 'rpm -q knot-resolver' (RHEL/CentOS). If running as a service, check 'kresd -h' for version information.
    Affected if Unable to determine the version (may indicate an unpatched or non-standard installation)
  3. Compare installed version against affected range
    If a version is obtained, verify it is less than 2.3.0. The affected version range is any knot-resolver version prior to 2.3.0. For example, versions like 2.2.0, 2.1.0, 2.0.0, or any 1.x release are all within the affected range.
    Affected if Installed version is 2.2.x, 2.1.x, 2.0.x, or any 1.x version (any version below 2.3.0)
  4. Verify the service is exposed to network DNS traffic
    Check if the knot-resolver service is listening on UDP/TCP port 53 (DNS). Review configuration files in /etc/knot-resolver/ or run 'netstat -tulnp | grep 53' or 'ss -tulnp | grep 53' to see if DNS ports are bound.
    Affected if The service is running and listening on DNS ports (53/UDP or 53/TCP), making it reachable to process incoming DNS queries

A system is affected if knot-resolver is installed with a version lower than 2.3.0 and the service is running and accessible to process DNS traffic on port 53.

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 2.3.0 or later
Fixed in 2.3.0
Interim mitigation

Update knot-resolver to version 2.3.0 or later to patch the vulnerability. Additionally, consider implementing DNS traffic filtering or rate limiting at network boundaries as a defense-in-depth measure.

Fix this in Knot Resolver Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

Scan for this in your stack

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dbcve dependency scanner

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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-2018-1110 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