What is the CVSS score of CVE-2026-33608?

CVE-2026-33608 has a CVSS 3.1 base score of 7.4 (High). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of PowerDNS Authoritative are affected by CVE-2026-33608?

CVE-2026-33608 affects PowerDNS Authoritative Server, allowing unauthenticated remote attackers to corrupt DNS configurations via malformed NOTIFY requests, causing persistent denial of service that…. A patch is available.

How to fix or mitigate CVE-2026-33608?

Within 24 hours: Identify all PowerDNS Authoritative Server instances exposed to untrusted networks and document current versions. Within 7 days: Implement network-level filtering to restrict DNS NOTIFY requests (port 53 TCP/UDP) to known secondary nameserver IP addresses only; disable NOTIFY reception if secondaries are not required. Within 30 days: Monitor vendor advisories for patch release and plan immediate deployment; evaluate alternative DNS solutions or air-gapped configuration management as contingency if patching timeline extends beyond acceptable risk tolerance.

PowerDNS Authoritative CVE-2026-33608

EUVD-2026-24945 HIGH

Code Injection (CWE-94)

2026-04-22 security@open-xchange.com

GHSA-q6jm-wh7h-j4g3

Code Injection RCE Suse

7.4

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.4 HIGH

AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H

SUSE

HIGH

qualitative

Primary rating from NVD.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

High

Lifecycle Timeline

Patch released

Apr 24, 2026 - 18:52 nvd

Patch available

Apr 22, 2026 - 16:33 EUVD

Re-analysis Queued

Apr 22, 2026 - 15:22 vuln.today

cvss_changed

Analysis Generated

Apr 22, 2026 - 15:00 vuln.today

EUVD ID Assigned

Apr 22, 2026 - 14:22 euvd

EUVD-2026-24945

Analysis Generated

Apr 22, 2026 - 14:22 vuln.today

CVE Published

Apr 22, 2026 - 14:16 nvd

HIGH 7.4

DescriptionCVE.org

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.

AnalysisAI

Remote attackers can corrupt PowerDNS Authoritative Server configuration via specially crafted DNS NOTIFY requests, causing persistent denial of service requiring manual administrator intervention. The attack adds malformed secondary domains to the bind backend, rendering the configuration invalid and preventing the server from restarting. No active exploitation confirmed at time of analysis, but the network-accessible attack vector and lack of authentication requirements elevate risk for internet-facing authoritative DNS servers.

Technical ContextAI

PowerDNS Authoritative Server uses modular backends for zone storage and management. The bind backend emulates BIND's zone file behavior and maintains its own configuration file tracking zone definitions. DNS NOTIFY (RFC 1996) is a mechanism where primary nameservers signal zone updates to secondaries. This vulnerability exploits the bind backend's NOTIFY request handling logic, which processes inbound notifications to dynamically add secondary zones. The flaw allows injection of malformed zone definitions that pass initial validation but create syntactically invalid backend configuration, corrupting the persistent state. The CWE classification is not provided, but the behavior aligns with improper input validation (CWE-20) combined with improper handling of exceptional conditions (CWE-755), where the backend fails to validate configuration integrity before committing changes to persistent storage.

RemediationAI

Consult the official PowerDNS security advisory at https://docs.powerdns.com/authoritative/security-advisories/powerdns-advisory-powerdns-2026-05.html for vendor-confirmed patch versions and upgrade instructions. Primary mitigation is upgrading PowerDNS Authoritative Server to the patched release specified in the advisory. For environments unable to immediately patch, implement compensating controls by restricting NOTIFY request sources using allow-notify-from directives to permit only trusted primary nameservers, effectively blocking untrusted attackers from triggering the vulnerability. This configuration change provides effective protection but requires maintaining accurate ACLs as DNS infrastructure evolves. Alternatively, if bind backend functionality is not operationally required, migrate zone data to alternative backends (such as generic SQL backends) which are not affected by this configuration corruption flaw. After any exploitation incident, manual recovery involves identifying corrupted zone definitions in the bind backend configuration file, removing malformed entries, and validating configuration syntax before service restart.