What’s Vulnerable › Vulnerabilities

CVE-2026-33258: Crafted zones can cause increased resource usage

• Severity: high (CVSS 7.5 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: 2026-04-22 · updated 2026-10-26
• Weakness: CWE-770

Description

By publishing and querying a crafted zone an attacker can cause allocation of large entries in the negative and aggressive NSEC(3) caches.

Affected products

• PowerDNS Recursor: from 5.2.0 before 5.2.9; from 5.3.0 before 5.3.6; 5.4.0 — fixed in 5.2.9, 5.3.6

How to fix

Upgrade to a fixed version: PowerDNS Recursor 5.2.9, 5.3.6. Check the vendor advisory for mitigations.

References

• https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-03.html

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