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
1
What is the severity of ZDI-26-584?
The severity of ZDI-26-584 is rated at 7.5 according to the CVSS.
2
What does the ZDI-26-584 vulnerability affect?
ZDI-26-584 affects installations of dnsmasq.
3
How do I fix ZDI-26-584?
To fix ZDI-26-584, update your dnsmasq installation to the latest version that addresses this vulnerability.
4
Is authentication required to exploit ZDI-26-584?
No, authentication is not required to exploit the ZDI-26-584 vulnerability.
5
What type of attack does ZDI-26-584 facilitate?
ZDI-26-584 facilitates a denial-of-service attack on affected dnsmasq installations.