Description
In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, insufficient validation of the RRSIG.Labels field combined with premature cache writes during RFC 8198 aggressive NSEC processing leads to cache poisoning that permits a malicious actor controlling a single delegated zone to poison arbitrary sibling zones under NSEC-signed parent domains. A malicious actor with one registered domain under an NSEC-signed TLD can serve malicious insecure DNS responses for unrelated sibling domains (sharing the same parent zone). Arbitrary delegations that do not exist under the parent domain and are covered by the parent's NSEC chain can be brought into insecure existence by fraudulent wildcard DS records (less labels than expected, unknown algorithm) from the malicious sibling domain. This allows the malicious actor to inject insecure wildcard records for those delegations.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| NLnet Labs | Unbound | 1.7.0 – < 1.25.2 | 1.25.2 |
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 | 1.25.2-1 | — |
| Debian 13 | unbound | 1.26.1-0+deb13u1 | — |
| Debian 12 | unbound | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | unbound | 1.25.1-1ubuntu3.1 | USN-8946-2 |
| Ubuntu 26.04 LTS | unbound | 1.24.2-1ubuntu2.4 | USN-8946-1 |
| Ubuntu 24.04 LTS | unbound | 1.19.2-1ubuntu3.12 | USN-8946-1 |
| Ubuntu 22.04 LTS | unbound | 1.13.1-1ubuntu5.17 | USN-8946-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | unbound | 1.9.4-2ubuntu1.11+esm3 | USN-8946-1 |
| Ubuntu Pro 18.04 LTS | unbound | 1.6.7-1ubuntu2.6+esm6 | USN-8946-1 |
| Ubuntu Pro 16.04 LTS | unbound | 1.5.8-1ubuntu1.1+esm5 | USN-8946-1 |
| Ubuntu Pro 14.04 LTS | unbound | 1.4.22-1ubuntu4.14.04.3+esm5 | USN-8946-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | unbound +6 | 1.24.2-7.el10_2.4 | RHSA-2026:55892 |
| RHEL 9 | unbound +4 | 1.24.2-3.el9_8.4 | RHSA-2026:55841 |
| RHEL 8 | unbound +3 | 1.16.2-5.14.el8_10 | RHSA-2026:55784 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | unbound +7 | 1.25.2-0.1.hum1 | RHSA-2026:43588 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | unbound +6 | 1.24.2-7.el10_2.4 | ALSA-2026:55892 |
| AlmaLinux 9 | unbound +4 | 1.24.2-3.el9_8.4 | ALSA-2026:55841 |
| AlmaLinux 8 | unbound +3 | 1.16.2-5.14.el8_10 | ALSA-2026:55784 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | unbound | 1.24.2-7.el10_2.4 | RLSA-2026:55892 |
| Rocky Linux 9 | unbound | 1.24.2-3.el9_8.4 | RLSA-2026:55841 |
| Rocky Linux 8 | unbound | 1.16.2-5.14.el8_10 | RLSA-2026:55784 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | unbound | 1.25.2-150600.23.19.1 | SUSE-SU-2026:3885-1 |
| SLES 15 SP6 | unbound | 1.25.2-150600.23.19.1 | SUSE-SU-2026:3885-1 |
| SLES 15 SP5 | unbound | 1.25.2-150100.10.28.1 | SUSE-SU-2026:3884-1 |
| SLES 15 SP4 | unbound | 1.25.2-150100.10.28.1 | SUSE-SU-2026:3884-1 |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | unbound | 1.25.2-160000.1.1 | SUSE-SU-2026:23226-1, SUSE-SU-2026:23215-1 |
| SLES for SAP 15 SP6 | unbound | 1.25.2-150600.23.19.1 | SUSE-SU-2026:3885-1 |
| SLES for SAP 15 SP5 | unbound | 1.25.2-150100.10.28.1 | SUSE-SU-2026:3884-1 |
| SLES for SAP 15 SP4 | unbound | 1.25.2-150100.10.28.1 | SUSE-SU-2026:3884-1 |
| SLES 16.0 | unbound | 1.25.2-160000.1.1 | SUSE-SU-2026:23226-1, SUSE-SU-2026:23215-1 |
| SLE Micro 6.2 | unbound | 1.25.2-160000.1.1 | SUSE-SU-2026:23050-1 |
| SLE Micro 6.1 | unbound | 1.25.2-slfo.1.1_1.1 | SUSE-SU-2026:23349-1 |
| SLE Micro 6.0 | unbound | 1.25.2-1.1 | SUSE-SU-2026:23360-1 |
| SLE Micro 5.5 | unbound | 1.25.2-150100.10.28.1 | SUSE-SU-2026:3884-1 |
| SLE HPC 15 SP5 | unbound | 1.25.2-150100.10.28.1 | SUSE-SU-2026:3884-1 |
| SLE HPC 15 SP4 | unbound | 1.25.2-150100.10.28.1 | SUSE-SU-2026:3884-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | unbound | 1.25.2-1.1 | openSUSE-SU-2026:11380-1 |
| openSUSE Leap 16.0 | unbound | 1.25.2-160000.1.1 | openSUSE-SU-2026:21550-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | unbound | 1.25.2-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.amzn2023.0.13 | ALAS2023-2026-2033 |
| Amazon Linux 2 | unbound +4 | 1.7.3-15.amzn2.0.15 | ALAS2-2026-3849 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | unbound | 1.25.2-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | unbound +6 | 1.24.2-7.el10_2.4 | ELSA-2026-55892 |
| Oracle Linux 9 | unbound +4 | 1.24.2-3.el9_8.4 | ELSA-2026-55841 |
| Oracle Linux 8 | unbound +3 | 1.16.2-5.14.el8_10 | ELSA-2026-55784 |
Advisories 29
- USN-8946-2 unbound vulnerabilities Ubuntu Security Notices (USN) · Nov 11, 2026
- WID-SEC-2026-2492 Unbound: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 10, 2026
- WID-SEC-2026-3595 IBM QRadar SIEM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 2, 2026
- ALSA-2026:55841 Important: unbound security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:55892 Important: unbound security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:55784 Important: unbound security update AlmaLinux Security Advisories · Oct 29, 2026
- USN-8946-1 unbound vulnerabilities Ubuntu Security Notices (USN) · Oct 21, 2026
- RHSA-2026:43588 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:55892 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 19, 2026
- RHSA-2026:55784 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 19, 2026
- RHSA-2026:55841 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 19, 2026
- SUSE-SU-2026:3885-1 Security update for unbound SUSE / openSUSE Security Updates · Sep 10, 2026
- SUSE-SU-2026:3884-1 Security update for unbound SUSE / openSUSE Security Updates · Sep 10, 2026
- SUSE-SU-2026:23360-1 Security update for unbound SUSE / openSUSE Security Updates · Sep 10, 2026
- SUSE-SU-2026:23349-1 Security update for unbound SUSE / openSUSE Security Updates · Sep 10, 2026
- SUSE-SU-2026:23226-1 Security update for unbound SUSE / openSUSE Security Updates · Aug 27, 2026
- SUSE-SU-2026:23215-1 Security update for unbound SUSE / openSUSE Security Updates · Aug 27, 2026
- WID-SEC-2026-3038 Meinberg LANTIME: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 26, 2026
- RLSA-2026:55892 Important: unbound security update Rocky Linux Security Advisories · Aug 18, 2026
- RLSA-2026:55784 Important: unbound security update Rocky Linux Security Advisories · Aug 18, 2026
- RLSA-2026:55841 Important: unbound security update Rocky Linux Security Advisories · Aug 18, 2026
- ELSA-2026-55892 Important: unbound security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Aug 17, 2026
- ELSA-2026-55841 Important: unbound security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Aug 17, 2026
- ELSA-2026-55784 Important: unbound security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Aug 17, 2026
- openSUSE-SU-2026:21550-1 Security update for unbound SUSE / openSUSE Security Updates · Aug 12, 2026
- SUSE-SU-2026:23050-1 Security update for unbound SUSE / openSUSE Security Updates · Aug 12, 2026
- ALAS2-2026-3849 Important: unbound security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Aug 4, 2026
- ALAS2023-2026-2033 Important: unbound security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Aug 4, 2026
- openSUSE-SU-2026:11380-1 libunbound8-1.25.2-1.1 on GA media SUSE / openSUSE Security Updates · Jul 27, 2026
References
- https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-44690.txt vendor-advisory