Any remote client can crash a (debugging/non-release build type) NSD serve child by sending it a special crafted message with a specially tuned number of DNS Cookie options (17 when UDP payload size is 512). By continuously crashing the serve childs, the remote client can severely hamper or, when positioned sufficiently close, deny all DNS service.
History

Tue, 01 Sep 2026 14:45:00 +0000

Type Values Removed Values Added
First Time appeared Nlnetlabs
Nlnetlabs nsd
Vendors & Products Nlnetlabs
Nlnetlabs nsd

Wed, 26 Aug 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 26 Aug 2026 08:45:00 +0000

Type Values Removed Values Added
Description Any remote client can crash a (debugging/non-release build type) NSD serve child by sending it a special crafted message with a specially tuned number of DNS Cookie options (17 when UDP payload size is 512). By continuously crashing the serve childs, the remote client can severely hamper or, when positioned sufficiently close, deny all DNS service.
Title Remote UDP DoS by sending multiple DNS Cookie options
Weaknesses CWE-400
CWE-617
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: NLnet Labs

Published: 2026-08-26T08:44:08.078Z

Updated: 2026-08-26T14:16:26.813Z

Reserved: 2026-08-10T07:31:26.962Z

Link: CVE-2026-19401

cve-icon Vulnrichment

Updated: 2026-08-26T14:13:35.555Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-08-26T09:16:45.857

Modified: 2026-09-01T21:03:04.987

Link: CVE-2026-19401

cve-icon Redhat

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