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Vulnerabilities

Vulnerability · CVE-2026-4890

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

Published May 11, 2026 · catalog updated Aug 25, 2026 · ZDI-26-584: dnsmasq DNSSEC NSEC/NSEC3

Check if you run it

No confirmed exploitation is on record for CVE-2026-4890. EPSS is 1.07%. Act only if a listed version of ZDI-26-584: dnsmasq DNSSEC NSEC/NSEC3 is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (ZDI-26-584: dnsmasq DNSSEC NSEC/NSEC3).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.07%
Remediation
Not established
Affected products
See sources for product scope

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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-4890

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-4890. EPSS is 1.07%. Act only if a listed version of ZDI-26-584: dnsmasq DNSSEC NSEC/NSEC3 is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-835: Infinite Loop. EPSS 1.07%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 13, 2026 · Catalog

    Detected

    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.

  2. Aug 25, 2026 · NIST NVD

    Updated

    A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.

Sources

  • CVE.orgVulnerability recordCVE-2026-4890

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-4890

    30-day exploitation probability 1.1%

    first.org
  • NIST NVDVulnerability recordCVE-2026-4890

    A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.

    nvd.nist.gov
  • Zero Day InitiativeCoordinated disclosureZDI-26-584

    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.

    zerodayinitiative.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.