CVE-2024-25581
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 · uneditedWhen incoming DNS over HTTPS support is enabled using the nghttp2 provider, and queries are routed to a tcp-only or DNS over TLS backend, an attacker can trigger an assertion failure in DNSdist by sending a request for a zone transfer (AXFR or IXFR) over DNS over HTTPS, causing the process to stop and thus leading to a Denial of Service. DNS over HTTPS is not enabled by default, and backends are using plain DNS (Do53) by default.
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 confidenceIn DNSdist, when incoming DNS over HTTPS (DoH) is enabled using the nghttp2 provider and queries are routed to a TCP-only or DNS over TLS (DoT) backend, a specially crafted zone transfer request (AXFR or IXFR) sent over DoH triggers an assertion failure, causing the DNSdist process to crash and resulting in Denial of Service.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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 checksWork through these to decide whether this CVE applies to you.
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Check DNSdist versionRun 'dnsdist --version' or check the installed package version to determine the exact version number, then compare it to the affected version ranges for CVE-2024-25581.Affected if The installed version falls within the vulnerable version range.
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Verify DoH is enabled with nghttp2Inspect the dnsdist configuration file (typically /etc/dnsdist.conf or /etc/dnsdist/dnsdist.conf) or run 'dnsdist -l' to list listeners. Look for 'addDOH()' or 'DOHFrontend' configuration using the nghttp2 provider.Affected if DoH is enabled and configured to use the nghttp2 provider.
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Identify TCP-only and DoT backendsReview the dnsdist configuration for backend server definitions using 'newServer()' with 'tcpOnly=true' or 'doT=true' parameters. Run 'dnsdist -v' or query the API to list configured backends and their types.Affected if Any backend is configured as TCP-only or uses DNS over TLS (DoT).
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Check routing from DoH to TCP-only/DoT backendsExamine dnsdist routing rules (via 'getRule()' API or configuration) to see if there are rules that direct DoH queries to the identified TCP-only or DoT backends, or verify the default backend pool includes such backends.Affected if DoH frontend queries can be routed to TCP-only or DoT backends.
The environment is affected if DNSdist with DoH (nghttp2) is configured and can route zone transfer queries (AXFR/IXFR) received over DoH to TCP-only or DoT backends.
Generated from the published advisory. Verify against your own configuration.
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 dataIf DoH is not required, ensure it remains disabled. If DoH is enabled, avoid routing zone transfer queries to TCP-only or DoT backends, or implement query type filtering to block AXFR/IXFR over DoH connections.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2024-25581 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2024-25581 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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