CVE-2026-44608
Fixed in a distro release EPSS <1%CVSS 4.6
NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a locking inconsistency vulnerability that when certain conditions are met (multi-threaded, RPZ XFR reload, RPZ zone with 'rpz-nsip'/'rpz-nsdname' triggers) it could result in heap use-after-free and eventual crash. An adversary can exploit the vulnerability if conditions are first met on a vulnerable Unbound, i.e., multi-threaded, an RPZ zone with 'rpz-nsip'/'rpz-nsdname' triggers and an ongoing XFR for that RPZ zone. Local RPZ files do not trigger the vulnerability. If the timing is right and an XFR happens at the same time another thread needs to read that RPZ zone, the reader may not hold the lock long enough and the thread applying the XFR may free objects that the reader is about to walk causing the use-after-free. Unbound 1.25.1 contains a patch with a fix to the locking code.
Products: NLnet Labs unbound
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Alpine 3.22 | unbound | 1.25.2-r0 |
| Alpine 3.23 | unbound | 1.25.2-r0 |
| Alpine 3.24 | unbound | 1.25.1-r0 |
| Amazon Linux 2023 | python3-unbound | 1.17.1-1.amzn2023.0.12 |
| Amazon Linux 2023 | unbound | 1.17.1-1.amzn2023.0.12 |
| Amazon Linux 2023 | unbound-anchor | 1.17.1-1.amzn2023.0.12 |
| Amazon Linux 2023 | unbound-devel | 1.17.1-1.amzn2023.0.12 |
| Amazon Linux 2023 | unbound-libs | 1.17.1-1.amzn2023.0.12 |
| Amazon Linux 2023 | unbound-utils | 1.17.1-1.amzn2023.0.12 |
| Debian 12 | unbound | no fix |
| Debian 13 | unbound | 1.22.0-2+deb13u3 |
| Debian 14 | unbound | 1.25.1-1 |
| Red Hat hummingbird 1 | python3-unbound | 0:1.25.1-0.1.hum1 |
| Red Hat hummingbird 1 | unbound | 0:1.25.1-0.1.hum1 |
| Red Hat hummingbird 1 | unbound-anchor | 0:1.25.1-0.1.hum1 |
| Red Hat hummingbird 1 | unbound-devel | 0:1.25.1-0.1.hum1 |
| Red Hat hummingbird 1 | unbound-dracut | 0:1.25.1-0.1.hum1 |
| Red Hat hummingbird 1 | unbound-libs | 0:1.25.1-0.1.hum1 |
| Red Hat hummingbird 1 | unbound-munin | 0:1.25.1-0.1.hum1 |
| Red Hat hummingbird 1 | unbound-utils | 0:1.25.1-0.1.hum1 |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | unbound | 1.20.0-150100.10.25.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | unbound | 1.20.0-150100.10.25.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | unbound | 1.20.0-150100.10.25.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | unbound | 1.20.0-150100.10.25.1 |
| SUSE Linux Enterprise Micro 5.5 | unbound | 1.20.0-150100.10.25.1 |
| SUSE Linux Enterprise Server 15 SP4-LTSS | unbound | 1.20.0-150100.10.25.1 |
| SUSE Linux Enterprise Server 15 SP5-LTSS | unbound | 1.20.0-150100.10.25.1 |
| SUSE Linux Enterprise Server 16.0 | unbound | 1.24.1-160000.2.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | unbound | 1.20.0-150100.10.25.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | unbound | 1.20.0-150100.10.25.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | unbound | 1.24.1-160000.2.1 |
| SUSE Linux Micro 6.2 | unbound | 1.24.1-160000.2.1 |
| Ubuntu 22.04 LTS | unbound | 1.13.1-1ubuntu5.15 |
| Ubuntu 24.04 LTS | unbound | 1.19.2-1ubuntu3.8 |
| Ubuntu 25.10 | unbound | 1.22.0-2ubuntu2.3 |
| Ubuntu 26.04 LTS | unbound | 1.24.2-1ubuntu2.1 |
| Ubuntu Pro 16.04 LTS | unbound | no fix |
| openSUSE Leap 16.0 | unbound | 1.24.1-160000.2.1 |
| openSUSE Tumbleweed | unbound | 1.25.1-1.1 |