Description
nsd-checkzone in NLnet Labs NSD 4.2.0 has a Stack-based Buffer Overflow in the dname_concatenate() function in dname.c.
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 | 4.2.4-1 | — |
| Debian 13 | nsd | 4.2.4-1 | — |
| Debian 12 | nsd | 4.2.4-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | nsd | No fix yet | — |
| Ubuntu 25.10 | nsd | No fix yet | — |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | nsd | No fix yet | — |
| Ubuntu Pro 24.04 LTS | nsd | No fix yet | — |
| Ubuntu Pro 22.04 LTS | nsd | No fix yet | — |
| Ubuntu Pro 20.04 LTS | nsd | No fix yet | — |
| Ubuntu Pro 18.04 LTS | nsd | No fix yet | — |
| Ubuntu Pro 16.04 LTS | nsd | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP2 | nsd | 4.3.4-bp152.2.3.1 | openSUSE-SU-2020:2222-1 |
| SUSE Package Hub 15 SP1 | nsd | 4.3.4-bp152.2.3.1 | openSUSE-SU-2020:2222-1 |
| SUSE Package Hub 12 | nsd | 4.3.4-bp152.2.3.1 | openSUSE-SU-2020:2222-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | nsd | 4.3.7-1.2 | openSUSE-SU-2024:11100-1 |
| openSUSE Leap 15.2 | nsd | 4.3.4-bp152.2.3.1 | openSUSE-SU-2020:2222-1 |
| openSUSE Leap 15.1 | nsd | 4.3.4-bp152.2.3.1 | openSUSE-SU-2020:2222-1 |
Advisories 2
- openSUSE-SU-2020:2222-1 Security update for nsd SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:11100-1 nsd-4.3.7-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://github.com/NLnetLabs/nsd/issues/20
- FEDORA-2019-96fe76e02b vendor-advisory