CVE-2026-45557: Technitium DNS Server excessive DNSSEC requests

Severity: medium (CVSS 5.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-19 · updated 2026-07-24
Weakness: CWE-405

Description

Technitium DNS Server aggressively tries to fetch missing RRSIG records or mismatched DNSKEY records. An attacker in control of a domain can cause a vulnerable system to generate excessive network traffic. Fixed in 15.0.

Affected products

Technitium DNS Server: before 15.0 — fixed in 15.0

How to fix

Upgrade to a fixed version: Technitium DNS Server 15.0. Check the vendor advisory for mitigations.

References

https://github.com/TechnitiumSoftware/DnsServer/blo/master/CHANGELOG.md#version-150
https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2025/va-26-138-02.json
https://www.cve.org/CVERecord?id=CVE-2026-45557

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