Description
validator/val_nsec3.c in Unbound before 1.4.13p2 does not properly perform proof processing for NSEC3-signed zones, which allows remote DNS servers to cause a denial of service (daemon crash) via a malformed response that lacks expected NSEC3 records, a different vulnerability than CVE-2011-4528.
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 | unbound | 1.4.14-1 | — |
| Debian 13 | unbound | 1.4.14-1 | — |
| Debian 12 | unbound | 1.4.14-1 | — |
| Debian 6.0 | unbound | 1.4.6-1+squeeze2 | DSA-2370-1 |
| Debian 5.0 | unbound | 1.4.6-1~lenny2 | DSA-2370-1 |
Advisories 1
- DSA-2370-1 unbound - several Debian Security (DSA / DLA) · Mar 9, 2026
References
- http://unbound.nlnetlabs.nl/downloads/CVE-2011-4528.txt
- 47326 third-party-advisory
- VU#209659 third-party-advisory
- unbound-nsec3-dos(71868) vdb-entry
- DSA-2370 vendor-advisory
- FEDORA-2011-17337 vendor-advisory
- FEDORA-2011-17282 vendor-advisory
- 77910 vdb-entry