---
id: CVE-2026-101337
title: >-
  When base64 data is split up in pieces, of 3 character or less, tokens were
  incorrectly calculated to produce 0 bytes
summary: >-
  When base64 data is split up in pieces, of 3 character or less, tokens were
  incorrectly calculated to produce 0 bytes. This enables attackers to overwrite
  the stack with up to 64K of attacker controlled data.  Zone files which are
  writte…
severity: none
cwe:
  - CWE-121
published: '2026-10-14'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T11:16:56.890'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-101337'
references:
  - url: 'https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-101337.txt'
    label: sep@nlnetlabs.nl
tags:
  - nvd
ingestedAt: '2026-10-14T11:27:22.140Z'
---

## Overview

When base64 data is split up in pieces, of 3 character or less, tokens were incorrectly calculated to produce 0 bytes. This enables attackers to overwrite the stack with up to 64K of attacker controlled data.  Zone files which are written out by NSD itself, such as for zones for which the NSD instance is secondary, will not be formatted like this. The zone file must be fed to NSD directly, (but it could come, for example, from an operator controlled provisioning system).

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.