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
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| NLnet Labs | NSD | 4.14.0 – < 4.14.3 | 4.14.3 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | nsd | 4.14.3-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | nsd | No fix yet | — |
| Ubuntu 25.10 | nsd | No fix yet | — |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | nsd | 4.14.0-1ubuntu0.1~esm1 | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | nsd | 4.14.3-1.1 | openSUSE-SU-2026:11395-1 |
| openSUSE Leap 16.0 | nsd | 4.14.3-bp160.1.1 | openSUSE-SU-2026:21502-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | nsd | 4.14.3-r0 | — |
Advisories 3
- WID-SEC-2026-3663 OpenBSD: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 29, 2026
- openSUSE-SU-2026:21502-1 Security update for nsd SUSE / openSUSE Security Updates · Jul 31, 2026
- openSUSE-SU-2026:11395-1 nsd-4.14.3-1.1 on GA media SUSE / openSUSE Security Updates · Jul 29, 2026
References
- https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-12244.txt vendor-advisory