Possible ZONEMD verification bypass window (NLnet Labs Unbound)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.17 % · percentile 7 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- NLnet Labs
- NVD status
- Analyzed
Description
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.
Weaknesses (CWE)
- CWE-345 — Insufficient Verification of Data Authenticity
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 4.4 | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N | NLnet Labs |
| CVSS 3.1 | MEDIUM 4.4 | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N | NVD · sep@nlnetlabs.nl (Secondary) |
European references
- ENISA EUVD · EUVD-2026-80287
- GCVE · GCVE-0-2026-77955
Affected configurations (NVD CPE)
cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*≥ 1.13.2 < 1.26.1
Affected products
| Product | Versions |
|---|---|
| NLnet Labs · Unbound | affected 1.13.2 < 1.26.1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |