CVE-2026-24029
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 the early_acl_drop (earlyACLDrop in Lua) option is disabled (default is enabled) on a DNS over HTTPs frontend using the nghttp2 provider, the ACL check is skipped, allowing all clients to send DoH queries regardless of the configured ACL.
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 confidenceWhen the early_acl_drop option is disabled on a DNS over HTTPS frontend using the nghttp2 provider, HAProxy skips the ACL check entirely, allowing all clients to bypass configured access controls and send DoH queries regardless of ACL rules.
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>= 1.9.0, < 1.9.12>= 2.0.0, < 2.0.3CVSS 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
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
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 package manager to determine the installed version of Powerdns dnsdistAffected if The installed version falls within 1.9.0 to 1.9.11, or 2.0.0 to 2.0.2
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Locate dnsdist configurationFind the dnsdist configuration file, typically at /etc/dnsdist.conf or as specified in the dnsdist startup parametersAffected if Configuration file exists and contains DoH frontend definitions
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Check early_acl_drop settingSearch the configuration file for 'earlyACLDrop' or 'setEarlyACLDrop' and verify whether it has been explicitly set to false or disabledAffected if early_acl_drop is explicitly set to false, disabled, or setNoEarlyACLDrop is configured on DoH frontends
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Verify DoH frontend configurationLook for 'DOHFrontend', 'addDOHBackend', or similar DoH-related directives in the configurationAffected if DNS over HTTPS frontends are configured and early_acl_drop is disabled for those frontends
A user is affected if running a vulnerable dnsdist version AND has explicitly disabled the early_acl_drop option on a DoH frontend, allowing unauthenticated clients to bypass ACL controls.
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.
dbcve · scoped1.9.122.0.3
Re-enable the early_acl_drop option on DoH frontends using nghttp2 to ensure ACL checks are enforced, or upgrade to a version where this behavior is fixed.
dnsdist 1.9.12 or 2.0.3 (depending on your major version branch)
- 1. Identify the current dnsdist version using 'dnsdist --version'
- 2. For dnsdist 1.9.x installations: upgrade to version 1.9.12 or later
- 3. For dnsdist 2.0.x installations: upgrade to version 2.0.3 or later
- 4. Verify the upgrade was successful by running 'dnsdist --version'
- 5. Review DoH frontend configurations to confirm early_acl_drop setting (default is enabled, which is secure)
- 6. Restart dnsdist service to apply the changes
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-24029 — 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-2026-24029 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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