CVE-2026-12246: CWE-120: Buffer Copy without Checking Size of Input in NLnet Labs NSD
A buffer overflow vulnerability exists in NLnet Labs NSD version 4.14.0 due to improper handling of a specially crafted APL resource record with an adflength larger than allowed. This causes a stack overwrite of up to 111 attacker-controlled bytes when the zone is written to disk. The vulnerability is classified as CWE-120 (Buffer Copy without Checking Size of Input) and has a high severity rating with a CVSS score of 7.2.
AI Analysis
Technical Summary
NLnet Labs NSD version 4.14.0 contains a buffer overflow vulnerability triggered by a malformed APL RR where the adflength exceeds the permitted size for the address family. This flaw leads to a stack overwrite of up to 111 bytes controlled by an attacker during zone file writes. The issue stems from a lack of proper input size validation before copying data, categorized under CWE-120. No official patch or remediation level has been published by the vendor as of the data provided.
Potential Impact
Successful exploitation can result in a stack-based buffer overflow, potentially allowing an attacker with low privileges to corrupt memory during zone writes. This may lead to denial of service or other undefined behavior due to memory corruption. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid using NSD version 4.14.0 or restrict processing of untrusted zone data that could contain malicious APL RRs. Monitor NLnet Labs communications for updates on patches or workarounds.
CVE-2026-12246: CWE-120: Buffer Copy without Checking Size of Input in NLnet Labs NSD
Description
A buffer overflow vulnerability exists in NLnet Labs NSD version 4.14.0 due to improper handling of a specially crafted APL resource record with an adflength larger than allowed. This causes a stack overwrite of up to 111 attacker-controlled bytes when the zone is written to disk. The vulnerability is classified as CWE-120 (Buffer Copy without Checking Size of Input) and has a high severity rating with a CVSS score of 7.2.
CVSS v4.0
Score 7.2high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
NLnet Labs NSD version 4.14.0 contains a buffer overflow vulnerability triggered by a malformed APL RR where the adflength exceeds the permitted size for the address family. This flaw leads to a stack overwrite of up to 111 bytes controlled by an attacker during zone file writes. The issue stems from a lack of proper input size validation before copying data, categorized under CWE-120. No official patch or remediation level has been published by the vendor as of the data provided.
Potential Impact
Successful exploitation can result in a stack-based buffer overflow, potentially allowing an attacker with low privileges to corrupt memory during zone writes. This may lead to denial of service or other undefined behavior due to memory corruption. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid using NSD version 4.14.0 or restrict processing of untrusted zone data that could contain malicious APL RRs. Monitor NLnet Labs communications for updates on patches or workarounds.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- NLnet Labs
- Date Reserved
- 2026-06-15T06:47:44.761Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a3cceac4853345fc182780c
Added to database: 06/25/2026, 06:46:04 UTC
Last enriched: 06/25/2026, 07:00:59 UTC
Last updated: 06/25/2026, 07:46:29 UTC
Views: 4
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