High severity · published Aug 26, 2026
CVE-2026-18916
Remote TCP DoS by throttling the TCP receive window
7.5
CVSS
0.5%
EPSS
No
On KEV
Description
Any remote client can crash a NSD serve child, by throttling the TCP receive window after a TCP query. By continuously crashing the serve childs, the remote client can denial all TCP service to this NSD instance.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 40% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NS
NSD · NLnet Labs
3.2.11 before 4.15.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-18916
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-18916
Vendor Advisory
https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-18916.txt
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