VIR Vulnerability Intelligence Relay

CVE-2026-77955

medium
Published 2026-09-16 · Modified 2026-09-16
Discuss on Community Propose mitigation
CVSS v3
4.4
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N
CVSS v4 NEW
—
not yet in upstream
VIR risk
4.4

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.

Predictions

Exploit likelihood
54%
Patch ETA
—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

References

CWEs

CWE-345

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.