Buffer Overflow Vulnerability in NSD by NLnet Labs
CVE-2026-101338

8.7HIGH

Key Information:

Vendor

Nlnet Labs

Status
Nsd
Vendor
CVE Published:
14 October 2026

What is CVE-2026-101338?

A vulnerability exists within the NSD DNS server that can be exploited when a Service Binding or HTTPS Resource Record (RR) exceeds its designated size in the wire format. In such cases, additional Entropy Contribution Hash (ECH) parameters may overwrite allocated stack memory, allowing an attacker to manipulate the base64 decoder. This manipulation can lead to the execution of arbitrary code or disruptions in service. The issue predominantly affects zone files provided directly to NSD, including those sourced from operator-controlled provisioning systems.

Affected Version(s)

NSD 4.10.0 < 4.15.3

References

https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-101338.txt
vendor-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Qifan Zhang from Palo Alto Networks
.