CVE-2026-12246 PUBLISHED

Out of bounds stack write with crafted APL RR

Assigner: NLnet Labs
Reserved: 15.06.2026 Published: 25.06.2026 Updated: 25.06.2026

NSD version 4.14.0 introduced a bug where a specially crafted APL RR, with an adflength larger than permitted for the address family will overwrite the stack when the zone is written to disk, with a maximum of 111 attacker controlled bytes.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 7.2

Processing of a zone containing a crafted APL can crash NSD when writing the zone to disk. These zones can be provided by a trusted primary

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	Low
User Interaction	None

Processing of a zone containing a crafted APL can crash NSD when writing the zone to disk. These zones can be provided by a trusted primary

CVSS 4.0

Product Status

Vendor	NLnet Labs
Product	NSD
Versions	Default: unaffected affected from 4.14.0 to 4.14.3 (excl.)

Solutions

This issue is fixed starting with version 4.14.3.

Credits

Qifan Zhang from Palo Alto Networks finder
Haruki Oyama from Waseda University finder
zhangph finder

References

https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-12246.txt

Problem Types

CWE-120: Buffer Copy without Checking Size of Input CWE
CWE-20: Improper Input Validation CWE