CVE-2026-12244

Heap overflow and crash with crafted SVCB RR

State: Published
Severity: 8.7 High
Published: Jun 25, 2026
Updated: Jun 25, 2026
Reserved: Jun 15, 2026

Description

If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a DNS message with a special crafted SVCB RR with an rdata size of 65512, that let's an (uint16_t) variable that is used to allocate space needed for the RR wrap (because total size > 65535), causing a heap overflow. The attacker can perform a controlled (RCE class) head write of up to 65509 bytes

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	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	NLnet Labs

Weaknesses

CWE-190 Integer Overflow or Wraparound
CWE-122 Heap-based Buffer Overflow

Affected Products

Product	Versions
NSDNLnet Labs	4.14.0 to before 4.14.3Affected

References

https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-12244.txtvendor-advisory

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