dbcve.org
AuthoritativeApplication · Powerdns

CVE-2026-33608

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-22
Fix available
A fix is available. Upgrade to 4.9.14 / 5.0.4 or later.
See remediation →
100/100
Remediation priority · Urgent
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 attacker can send a notify request that causes a new secondary domain to be added to the bind backend, but causes said backend to update its configuration to an invalid one, leading to the backend no longer able to run on the next restart, requiring manual operation to fix it.

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

This is a BIND DNS server vulnerability where a specially crafted DNS NOTIFY request can cause the bind backend to add a new secondary (slave) domain while simultaneously corrupting its own configuration. The corrupted configuration prevents the DNS backend from restarting, effectively causing a denial of service that requires manual remediation.

MitigationApply any available BIND security updates or patches for this vulnerability; until patched, restrict DNS NOTIFY access to trusted secondary DNS servers only.

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
AuthoritativeApplication
Affected:>= 4.9.0, < 4.9.14>= 5.0.0, < 5.0.4

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 Powerdns Authoritative version
    Run 'pdns --version' or 'pdns_server --version' to get the exact installed version number
    Affected if Version is 4.9.0 through 4.9.13, or 5.0.0 through 5.0.3 (vulnerable ranges)
  2. Verify secondary DNS support is enabled
    Check the pdns.conf configuration file (typically /etc/powerdns/pdns.conf) for 'secondary=yes' or 'allow-axfr-ips' settings
    Affected if Secondary support is enabled (the feature must be active for the flaw to be exploitable)
  3. Confirm DNS service is listening on external interfaces
    Run 'netstat -tulnp | grep pdns' or 'ss -tulnp | grep pdns' to see if the DNS service is bound to external IP addresses
    Affected if The service is reachable from untrusted networks on port 53 (UDP/TCP)
  4. Check configuration integrity for invalid secondary zones
    Run 'pdns_control list-zones' to enumerate configured zones, then review pdns.conf for unexpected or corrupted secondary zone definitions
    Affected if Unexpected secondary zones appear in configuration or zones cannot be listed without errors
  5. Verify service restart capability
    Attempt 'pdns_control quit' followed by starting pdns, or check systemd service status with 'systemctl status pdns'
    Affected if Service fails to restart or enters a failed state after attempting to reload configuration

You are affected if running a vulnerable version (4.9.x < 4.9.14 or 5.0.x < 5.0.4) with secondary DNS support enabled and the service is exposed to untrusted DNS notify 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.

dbcve · scoped
Upgrade available Upgrade to 4.9.14 / 5.0.4 or later
Fixed in 4.9.145.0.4
Interim mitigation

Apply any available BIND security updates or patches for this vulnerability; until patched, restrict DNS NOTIFY access to trusted secondary DNS servers only.

Recommended fix High confidence

Upgrade to PowerDNS Authoritative Server 4.9.14 (for 4.9.x users) or 5.0.4 (for 5.0.x users)

  1. 1. Identify current PowerDNS Authoritative Server version using 'pdns --version' or checking package version
  2. 2. If running 4.9.x (>=4.9.0, <4.9.14), plan upgrade to 4.9.14
  3. 3. If running 5.0.x (>=5.0.0, <5.0.4), plan upgrade to 5.0.4
  4. 4. Take a backup of current configuration files (/etc/pdns/, /etc/powerdns/)
  5. 5. Test the upgrade in a staging environment before production deployment
  6. 6. Upgrade the package using your package manager (e.g., apt-get update && apt-get install pdns-authoritative, or yum/dnf update pdns-authoritative)
  7. 7. Verify the new version is installed (pdns --version)
  8. 8. Restart the PowerDNS service (systemctl restart pdns or equivalent)
Caveat Review release notes for any configuration or behavior changes between your current version and the target fixed version before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Authoritative Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2026-33608 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