CVE-2026-19401: CWE-617 Reachable Assertion in NLnet Labs NSD
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.
CVE-2026-19401: CWE-617 Reachable Assertion in NLnet Labs NSD
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.
CVSS v4.0
Score 8.2high
Affected software
Weaknesses
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- NLnet Labs
- Date Reserved
- 2026-08-10T07:31:26.962Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a8ea959acd9273b499fef54
Added to database: 08/26/2026, 08:52:41 UTC
Last updated: 08/26/2026, 15:28:57 UTC
Views: 7
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