CVE-2026-81634
Fixed in a distro release EPSS <1%CVSS 7.5
In NLnet Labs Unbound up to and including 1.26.0, a 255 length query name with a large TCP response can lead to a heap buffer overflow during the RRSet canonicalisation routine. This is caused by missing to add the first owner name into the buffer length check. A malicious actor operating a malicious name server or tampering with an incoming response to Unbound (canonicalisation happens before DNSSEC validation), can trigger the vulnerability.
Products: NLnet Labs unbound
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux 10 | python3-unbound | 1.24.2-7.el10_2.6 |
| AlmaLinux 10 | unbound | 1.24.2-7.el10_2.6 |
| AlmaLinux 10 | unbound-anchor | 1.24.2-7.el10_2.6 |
| AlmaLinux 10 | unbound-devel | 1.24.2-7.el10_2.6 |
| AlmaLinux 10 | unbound-dracut | 1.24.2-7.el10_2.6 |
| AlmaLinux 10 | unbound-libs | 1.24.2-7.el10_2.6 |
| AlmaLinux 10 | unbound-utils | 1.24.2-7.el10_2.6 |
| AlmaLinux 8 | python3-unbound | 1.16.2-5.14.el8_10.4 |
| AlmaLinux 8 | unbound | 1.16.2-5.14.el8_10.4 |
| AlmaLinux 8 | unbound-devel | 1.16.2-5.14.el8_10.4 |
| AlmaLinux 8 | unbound-libs | 1.16.2-5.14.el8_10.4 |
| AlmaLinux 9 | python3-unbound | 1.24.2-3.el9_8.8 |
| AlmaLinux 9 | unbound | 1.24.2-3.el9_8.8 |
| AlmaLinux 9 | unbound-devel | 1.24.2-3.el9_8.8 |
| AlmaLinux 9 | unbound-dracut | 1.24.2-3.el9_8.8 |
| AlmaLinux 9 | unbound-libs | 1.24.2-3.el9_8.8 |
| Amazon Linux 2 | python2-unbound | 1.7.3-15.amzn2.0.17 |
| Amazon Linux 2 | python3-unbound | 1.7.3-15.amzn2.0.17 |
| Amazon Linux 2 | unbound | 1.7.3-15.amzn2.0.17 |
| Amazon Linux 2 | unbound-devel | 1.7.3-15.amzn2.0.17 |
| Amazon Linux 2 | unbound-libs | 1.7.3-15.amzn2.0.17 |
| Amazon Linux 2023 | python3-unbound | 1.17.1-1.amzn2023.0.15 |
| Amazon Linux 2023 | unbound | 1.17.1-1.amzn2023.0.15 |
| Amazon Linux 2023 | unbound-anchor | 1.17.1-1.amzn2023.0.15 |
| Amazon Linux 2023 | unbound-devel | 1.17.1-1.amzn2023.0.15 |
| Amazon Linux 2023 | unbound-libs | 1.17.1-1.amzn2023.0.15 |
| Amazon Linux 2023 | unbound-utils | 1.17.1-1.amzn2023.0.15 |
| Debian 12 | unbound | no fix |
| Debian 13 | unbound | 1.26.1-0+deb13u1 |
| Debian 14 | unbound | 1.26.1-1 |
| Red Hat Enterprise Linux 10.2 | python3-unbound | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | python3-unbound-debuginfo | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound-anchor | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound-anchor-debuginfo | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound-debuginfo | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound-debugsource | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound-devel | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound-dracut | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound-libs | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound-libs-debuginfo | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound-utils | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 10.2 | unbound-utils-debuginfo | 0:1.24.2-7.el10_2.6 |
| Red Hat Enterprise Linux 8 | python3-unbound | 0:1.16.2-5.14.el8_10.4 |
| Red Hat Enterprise Linux 8 | python3-unbound-debuginfo | 0:1.16.2-5.14.el8_10.4 |
| Red Hat Enterprise Linux 8 | unbound | 0:1.16.2-5.14.el8_10.4 |
| Red Hat Enterprise Linux 8 | unbound-debuginfo | 0:1.16.2-5.14.el8_10.4 |
| Red Hat Enterprise Linux 8 | unbound-debugsource | 0:1.16.2-5.14.el8_10.4 |
| Red Hat Enterprise Linux 8 | unbound-devel | 0:1.16.2-5.14.el8_10.4 |
| Red Hat Enterprise Linux 8 | unbound-libs | 0:1.16.2-5.14.el8_10.4 |
| Red Hat Enterprise Linux 8 | unbound-libs-debuginfo | 0:1.16.2-5.14.el8_10.4 |
| Red Hat Enterprise Linux 9 | python3-unbound | 0:1.24.2-3.el9_8.8 |
| Red Hat Enterprise Linux 9 | python3-unbound-debuginfo | 0:1.24.2-3.el9_8.8 |
| Red Hat Enterprise Linux 9 | unbound | 0:1.24.2-3.el9_8.8 |
| Red Hat Enterprise Linux 9 | unbound-debuginfo | 0:1.24.2-3.el9_8.8 |
| Red Hat Enterprise Linux 9 | unbound-debugsource | 0:1.24.2-3.el9_8.8 |
| Red Hat Enterprise Linux 9 | unbound-devel | 0:1.24.2-3.el9_8.8 |
| Red Hat Enterprise Linux 9 | unbound-dracut | 0:1.24.2-3.el9_8.8 |
| Red Hat Enterprise Linux 9 | unbound-libs | 0:1.24.2-3.el9_8.8 |
| Red Hat Enterprise Linux 9 | unbound-libs-debuginfo | 0:1.24.2-3.el9_8.8 |
| Red Hat hummingbird 1 | python3-unbound | 0:1.26.1-1.hum1 |
| Red Hat hummingbird 1 | unbound | 0:1.26.1-1.hum1 |
| Red Hat hummingbird 1 | unbound-anchor | 0:1.26.1-1.hum1 |
| Red Hat hummingbird 1 | unbound-devel | 0:1.26.1-1.hum1 |
| Red Hat hummingbird 1 | unbound-dracut | 0:1.26.1-1.hum1 |
| Red Hat hummingbird 1 | unbound-libs | 0:1.26.1-1.hum1 |
| Red Hat hummingbird 1 | unbound-munin | 0:1.26.1-1.hum1 |
| Red Hat hummingbird 1 | unbound-utils | 0:1.26.1-1.hum1 |
| Rocky Linux 10 | unbound | 0:1.24.2-7.el10_2.6 |
| Rocky Linux 8 | unbound | 0:1.16.2-5.14.el8_10.4 |
| Rocky Linux 9 | unbound | 0:1.24.2-3.el9_8.8 |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | unbound | 1.26.1-150100.10.31.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | unbound | 1.26.1-150100.10.31.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | unbound | 1.26.1-150100.10.31.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | unbound | 1.26.1-150100.10.31.1 |
| SUSE Linux Enterprise Micro 5.5 | unbound | 1.26.1-150100.10.31.1 |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | unbound | 1.26.1-150600.23.24.1 |
| SUSE Linux Enterprise Module for Package Hub 15 SP7 | unbound | 1.26.1-150600.23.24.1 |
| SUSE Linux Enterprise Server 15 SP4-LTSS | unbound | 1.26.1-150100.10.31.1 |
| SUSE Linux Enterprise Server 15 SP5-LTSS | unbound | 1.26.1-150100.10.31.1 |
| SUSE Linux Enterprise Server 15 SP6-LTSS | unbound | 1.26.1-150600.23.24.1 |
| SUSE Linux Enterprise Server 16.0 | unbound | 1.26.1-160000.1.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | unbound | 1.26.1-150100.10.31.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | unbound | 1.26.1-150100.10.31.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | unbound | 1.26.1-150600.23.24.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | unbound | 1.26.1-160000.1.1 |
| SUSE Linux Micro 6.0 | unbound | 1.26.1-159998.1.1 |
| SUSE Linux Micro 6.2 | unbound | 1.26.1-160000.1.1 |
| Ubuntu 22.04 LTS | unbound | 1.13.1-1ubuntu5.17 |
| Ubuntu 24.04 LTS | unbound | 1.19.2-1ubuntu3.12 |
| Ubuntu 26.04 LTS | unbound | 1.24.2-1ubuntu2.4 |
| Ubuntu 26.10 | unbound | no fix |
| Ubuntu Pro 14.04 LTS | unbound | 1.4.22-1ubuntu4.14.04.3+esm5 |
| Ubuntu Pro 16.04 LTS | unbound | 1.5.8-1ubuntu1.1+esm5 |
| Ubuntu Pro 18.04 LTS | unbound | 1.6.7-1ubuntu2.6+esm6 |
| Ubuntu Pro 20.04 LTS | unbound | 1.9.4-2ubuntu1.11+esm3 |
| openSUSE Leap 16.0 | unbound | 1.26.1-160000.1.1 |
| openSUSE Tumbleweed | unbound | 1.26.1-1.1 |