Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| NLnet Labs | Unbound | 1.14.0 – < 1.25.1 | 1.25.1 |
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 | 1.25.1-1 | — |
| Debian 13 | unbound | 1.22.0-2+deb13u3 | — |
| Debian 12 | unbound | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | unbound | 1.24.2-1ubuntu2.1 | — |
| Ubuntu 25.10 | unbound | 1.22.0-2ubuntu2.3 | — |
| Ubuntu 24.04 LTS | unbound | 1.19.2-1ubuntu3.8 | — |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | unbound | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | unbound +6 | 1.26.1-2.el10_3 | RHSA-2026:97121 |
| RHEL 9 | unbound +4 | 1.26.1-1.el9_9 | RHSA-2026:97497 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | unbound +7 | 1.25.1-0.1.hum1 | RHSA-2026:19752 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | unbound +6 | 1.26.1-2.el10_3 | RLSA-2026:97121 |
| Rocky Linux 9 | unbound +4 | 1.26.1-1.el9_9 | RLSA-2026:97497 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP5 | unbound | 1.20.0-150100.10.25.1 | SUSE-SU-2026:2369-1 |
| SLES 15 SP4 | unbound | 1.20.0-150100.10.25.1 | SUSE-SU-2026:2369-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | unbound | 1.24.1-160000.2.1 | SUSE-SU-2026:22160-1 |
| SLES for SAP 15 SP5 | unbound | 1.20.0-150100.10.25.1 | SUSE-SU-2026:2369-1 |
| SLES for SAP 15 SP4 | unbound | 1.20.0-150100.10.25.1 | SUSE-SU-2026:2369-1 |
| SLES 16.0 | unbound | 1.24.1-160000.2.1 | SUSE-SU-2026:22160-1 |
| SLE Micro 6.2 | unbound | 1.24.1-160000.2.1 | SUSE-SU-2026:22213-1 |
| SLE Micro 5.5 | unbound | 1.20.0-150100.10.25.1 | SUSE-SU-2026:2369-1 |
| SLE HPC 15 SP5 | unbound | 1.20.0-150100.10.25.1 | SUSE-SU-2026:2369-1 |
| SLE HPC 15 SP4 | unbound | 1.20.0-150100.10.25.1 | SUSE-SU-2026:2369-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | unbound | 1.25.1-1.1 | openSUSE-SU-2026:10903-1 |
| openSUSE Leap 16.0 | unbound | 1.24.1-160000.2.1 | openSUSE-SU-2026:21083-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | unbound | 1.25.1-r0 | — |
| Alpine v3.23 | unbound | 1.25.2-r0 | — |
| Alpine v3.22 | unbound | 1.25.2-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | unbound +5 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | unbound | 1.25.1-1 | — |
Advisories 13
- RHSA-2026:97497 Red Hat Security Advisory: unbound security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:97121 Red Hat Security Advisory: unbound security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RLSA-2026:97497 Moderate: unbound security, bug fix, and enhancement update Rocky Linux Security Advisories · Nov 13, 2026
- RLSA-2026:97121 Moderate: unbound security, bug fix, and enhancement update Rocky Linux Security Advisories · Nov 13, 2026
- WID-SEC-2026-2455 Oracle Solaris Drittanbieterkomponenten: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- WID-SEC-2026-1599 Unbound: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 10, 2026
- RHSA-2026:19752 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 6, 2026
- openSUSE-SU-2026:21083-1 Security update for unbound SUSE / openSUSE Security Updates · Jun 30, 2026
- SUSE-SU-2026:22160-1 Security update for unbound SUSE / openSUSE Security Updates · Jun 24, 2026
- SUSE-SU-2026:22213-1 Security update for unbound SUSE / openSUSE Security Updates · Jun 24, 2026
- SUSE-SU-2026:2369-1 Security update for unbound SUSE / openSUSE Security Updates · Jun 12, 2026
- openSUSE-SU-2026:10903-1 libunbound8-1.25.1-1.1 on GA media SUSE / openSUSE Security Updates · May 30, 2026
- ALAS2023-2026-1756 Important: unbound security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · May 26, 2026
References
- https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-44608.txt vendor-advisory