Vulnerability DatabaseCVE-2026-19401
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CVE-2026-19401
Published:August 26, 2026
Updated:September 24, 2026
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.
Affected Packages
https://github.com/NLnetLabs/nsd.git (GITHUB):
Affected version(s) >=NSD_4_3_7_REL <NSD_4_15_1_REL
Fix Suggestion:
Update to version NSD_4_15_1_REL
Related Resources (2)
https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-19401.txt
https://nvd.nist.gov/vuln/detail/CVE-2026-19401
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CVSS v4
Base Score:
8.2
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Uncontrolled Resource Consumption
CWE-400
Reachable Assertion
CWE-617
EPSS
Base Score:
0.36