Vulnerability · Published Jun 25, 2026 · Assigned by NLnet Labs
CVE-2026-12246Out of bounds stack write with crafted APL RR
High 7.2
In plain English
A high-severity buffer overflow in NSD from NLnet Labs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)7.2High
Exploit odds (30 days)0.4%top 61.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | nsd | 4.14.3-r0 | ALPINE-CVE-2026-12246 |
| Debian:14 | nsd | 4.14.3-1 | DEBIAN-CVE-2026-12246 |
| Ubuntu:25.10 | nsd | no fix listed | UBUNTU-CVE-2026-12246 |
| Ubuntu:26.10 | nsd | no fix listed | UBUNTU-CVE-2026-12246 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| NLnet Labs | NSD | 4.14.0 – before 4.14.3 |
Weakness: CWE-120, CWE-20 · 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
References
- https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-12246.txt vendor-advisory