CVE-2026-77955
Fixed in a distro release EPSS <1%CVSS 4.4
In NLnet Labs Unbound 1.13.2 up to and including 1.26.1, a vulnerability in ZONEMD configured zones (zonemd-check: yes) which are located below (but not at) a trust anchor allow for an attack window where (tampered with) zone contents are served (or stored to disk) prior to the ZONEMD integrity check. This is caused by the needed DS/DNSKEY asynchronous resolution that needs to happen before the ZONEMD check completes. If a zonefile is written to disk (zonefile: option) while the ZONEMD check failed, the tampered data are reloaded on startup and available until ZONEMD verification concludes again. If verification fails, the data is not served any more but still persists on disk for future reloads.
Products: NLnet Labs unbound
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| 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 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 |
| 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 | no fix |
| Ubuntu 24.04 LTS | unbound | no fix |
| Ubuntu 26.04 LTS | unbound | no fix |
| Ubuntu 26.10 | unbound | no fix |
| Ubuntu Pro 14.04 LTS | unbound | no fix |
| Ubuntu Pro 16.04 LTS | unbound | no fix |
| Ubuntu Pro 18.04 LTS | unbound | no fix |
| Ubuntu Pro 20.04 LTS | unbound | no fix |
| openSUSE Leap 16.0 | unbound | 1.26.1-160000.1.1 |
| openSUSE Tumbleweed | unbound | 1.26.1-1.1 |