dbcve.org
DnsserverApplication · Technitium

CVE-2023-28451

HIGH · 7.5 CVSS v3.1 Published 2024-09-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
An issue was discovered in Technitium 11.0.2. There is a vulnerability (called BadDNS) in DNS resolving software, which triggers a resolver to ignore valid responses, thus causing DoS (denial of service) for normal resolution. The effects of an exploit would be widespread and highly impactful, because the attacker could just forge a response targeting the source port of a vulnerable resolver without the need to guess the correct TXID.

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

A vulnerability in Technitium DNS Proxy Server 11.0.2 allows remote attackers to cause the resolver to ignore valid DNS responses. Known as BadDNS, this flaw enables attackers to forge DNS responses targeting the source port without requiring knowledge of the correct TXID (transaction ID), which normally protects against DNS spoofing. This results in denial of service for legitimate DNS resolution.

MitigationUpdate Technitium DNS Proxy Server to the latest patched version. If no patched version is immediately available, consider implementing source port randomization and deploying DNSsec validation as temporary mitigations to reduce the attack surface.

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
DnsserverApplication
Affected:= 11.0.2

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. Identify Technitium DNS Server installation
    Check for the presence of the Technitium DNS Server process or service running on the system. On Windows, look for 'DnsServer.exe' in Task Manager or as a Windows service. On Linux, check for the 'dns' process or look in the installation directory (typically /opt/dns or /var/lib/dns).
    Affected if Technitium DNS Server is installed and running on the system.
  2. Determine the installed version
    Locate the version information for the installed Technitium DNS Server. On Windows, right-click the DnsServer.exe file, select Properties, and check the 'Details' tab for the 'File version'. On Linux, check the version file in the installation directory or run 'dns --version' if available. Alternatively, access the DNS server web interface (typically at http://localhost:5380) and look for the version number displayed on the dashboard or about page.
    Affected if Unable to determine the version from the installation.
  3. Compare version to affected range
    Verify if the installed version matches exactly 11.0.2. The vulnerability affects only this specific version. Any other version (older or newer) is not affected by this CVE.
    Affected if The installed version is confirmed to be exactly 11.0.2.
  4. Confirm DNS service is accessible
    Verify that the DNS service is bound to network interfaces accessible from untrusted networks. Check the DNS server configuration for allowed networks and ensure the service port (default UDP/TCP 53) is exposed to external traffic.
    Affected if The DNS server is reachable from untrusted or public networks, increasing exploitability.

A system is affected if it is running Technitium DNS Server version 11.0.2 specifically and the DNS service is accessible to potential attackers.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Technitium DNS Proxy Server to the latest patched version. If no patched version is immediately available, consider implementing source port randomization and deploying DNSsec validation as temporary mitigations to reduce the attack surface.

Fix this in Dnsserver Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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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-2023-28451 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
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