Description
Unbound before 1.9.4 accesses uninitialized memory, which allows remote attackers to trigger a crash via a crafted NOTIFY query. The source IP address of the query must match an access-control rule.
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 | 1.9.4-1 | — |
| Debian 13 | unbound | 1.9.4-1 | — |
| Debian 12 | unbound | 1.9.4-1 | — |
| Debian 10 | unbound | 1.9.0-2+deb10u1 | DSA-4544-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | unbound | 1.13.2-1.2 | openSUSE-SU-2024:11005-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | unbound | 1.9.4-r0 | — |
| Alpine v3.23 | unbound | 1.9.4-r0 | — |
| Alpine v3.22 | unbound | 1.9.4-r0 | — |
| Alpine v3.21 | unbound | 1.9.4-r0 | — |
| Alpine v3.20 | unbound | 1.9.4-r0 | — |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | unbound | 1.9.4-r0 | — |
| Alpine v3.18 | unbound | 1.9.4-r0 | — |
| Alpine v3.17 | unbound | 1.9.4-r0 | — |
| Alpine v3.16 | unbound | 1.9.4-r0 | — |
| Alpine v3.15 | unbound | 1.9.4-r0 | — |
| Alpine v3.14 | unbound | 1.9.4-r0 | — |
| Alpine v3.13 | unbound | 1.9.4-r0 | — |
| Alpine v3.12 | unbound | 1.9.4-r0 | — |
| Alpine v3.11 | unbound | 1.9.4-r0 | — |
| Alpine v3.10 | unbound | 1.9.1-r3 | — |
| Alpine v3.9 | unbound | 1.8.3-r2 | — |
| Alpine v3.8 | unbound | 1.7.3-r1 | — |
Advisories 2
- DSA-4544-1 unbound - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:11005-1 libunbound8-1.13.2-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://github.com/NLnetLabs/unbound/blob/release-1.9.4/doc/Changelog
- https://nlnetlabs.nl/downloads/unbound/CVE-2019-16866.txt
- USN-4149-1 vendor-advisory
- DSA-4544 vendor-advisory
- 20191016 [SECURITY] [DSA 4544-1] unbound security update mailing-list
- FEDORA-2019-e99b716a92 vendor-advisory
- FEDORA-2019-0418c12a36 vendor-advisory