Stack Overwrite Vulnerability in NSD by NLnet Labs
CVE-2026-101337

8.7HIGH

Key Information:

Vendor

Nlnet Labs

Status
Nsd
Vendor
CVE Published:
14 October 2026

What is CVE-2026-101337?

A vulnerability in NSD allows attackers to exploit issues in base64 data handling by splitting the data into pieces of three characters or less, leading to incorrect token calculations resulting in zero bytes. This can enable attackers to overwrite the stack with up to 64K of their controlled data. Specifically, the vulnerability arises when zone files generated by NSD are formatted incorrectly. For effective exploitation, zone files need to be provided directly to NSD, potentially originating from an operator-controlled provisioning system. This flaw highlights the importance of secure data handling practices.

Affected Version(s)

NSD 4.10.0 < 4.15.3

References

https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-101337.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
Gaurang Maheta
.