CVE-2023-26437: Deterred spoofing attempts can lead to authoritative servers being marked unavailable

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-04-04 · updated 2026-06-17
Weakness: CWE-400

Description

Denial of service vulnerability in PowerDNS Recursor allows authoritative servers to be marked unavailable.This issue affects Recursor: through 4.6.5, through 4.7.4 , through 4.8.3.

Affected products

PowerDNS Recursor: before 4.6.6; from 4.7.0 before 4.7.5; from 4.8.0 before 4.8.4 — fixed in 4.6.6, 4.7.5, 4.8.4

How to fix

Upgrade to a fixed version: PowerDNS Recursor 4.6.6, 4.7.5, 4.8.4. Check the vendor advisory for mitigations.

References

https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2023-02.html
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/CN7VMRYKZHG2UDUAK326LXD3JY7NO3LR/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IHPD6SIQOG7245GXFQHPUEI4AZ6Y3KD6/
https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2023-02.html
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/CN7VMRYKZHG2UDUAK326LXD3JY7NO3LR/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IHPD6SIQOG7245GXFQHPUEI4AZ6Y3KD6/

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