ZDI-26-584: dnsmasq DNSSEC NSEC/NSEC3 Type Bitmap Processing Infinite Loop Denial-of-Service Vulnerability

Published Aug 13, 2026

Updated

This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of dnsmasq. Authentication is not required to exploit this vulnerability. The ZDI has assigned a CVSS rating of 7.5. The following CVEs are assigned: CVE-2026-4890.

Affected Software

1 affected component

dnsmasq

Event History

Aug 13, 2026

Advisory Published

via ZDI·05:00 AM

Data Sourced

via ZDI·05:00 AM

Description

Frequently Asked Questions

What is the severity of ZDI-26-584?

The severity of ZDI-26-584 is rated at 7.5 according to the CVSS.

What does the ZDI-26-584 vulnerability affect?

ZDI-26-584 affects installations of dnsmasq.

How do I fix ZDI-26-584?

To fix ZDI-26-584, update your dnsmasq installation to the latest version that addresses this vulnerability.

Is authentication required to exploit ZDI-26-584?

No, authentication is not required to exploit the ZDI-26-584 vulnerability.

What type of attack does ZDI-26-584 facilitate?

ZDI-26-584 facilitates a denial-of-service attack on affected dnsmasq installations.

ZDI-26-584: dnsmasq DNSSEC NSEC/NSEC3 Type Bitmap Processing Infinite Loop Denial-of-Service Vulnerability

Affected Software

Event History

Don't miss critical vulnerabilities

Frequently Asked Questions

What is the severity of ZDI-26-584?

What does the ZDI-26-584 vulnerability affect?

How do I fix ZDI-26-584?

Is authentication required to exploit ZDI-26-584?

What type of attack does ZDI-26-584 facilitate?

Company

Resources

Contact

Frequently Asked Questions

What is the severity of ZDI-26-584?

What does the ZDI-26-584 vulnerability affect?

How do I fix ZDI-26-584?

Is authentication required to exploit ZDI-26-584?

What type of attack does ZDI-26-584 facilitate?