CVE-2026-101337

Stack overwrite from specially formatted base64 RDATA field

Published Oct 14, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
Description
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

Vendor Solution

This issue is fixed in 4.15.3 and all later versions.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Nlnetlabs
Nlnetlabs nsd
Vendors & Products Nlnetlabs
Nlnetlabs nsd
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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).
Title Stack overwrite from specially formatted base64 RDATA field
Weaknesses CWE-121
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
NLnet Labs
Published
Updated
Oct 14, 2026, 2:09 PM
Reserved
Sep 28, 2026, 2:39 PM
Status
Awaiting Analysis
Published
Oct 14, 2026, 11:16 AM
Modified
Oct 16, 2026, 7:55 PM