CVEvulnerability

CVE-2026-77955

4.4 MEDIUM Published 2026-09-16 Modified 2026-09-23 Official page ↗
Status
Analyzed
Published
2026-09-16
Last modified
2026-09-23
Assigner
[email protected]
CVSS 3.1 ([email protected])
4.4 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N
Weaknesses
CWE-345

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.

Affected configurations

• nlnetlabs unbound (>= 1.13.2 < 1.26.1)

Related

Weakness · CWE (1)

  • CWE-345 Insufficient Verification of Data Authenticity weakness

References