A validly signed NSEC3 from an unrelated sibling zone may be accepted as an insecurity proof, downgrading a secure delegation and letting a forged unsigned answer through.
This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.
Advisories

No advisories yet.

Fixes

Solution

Upgrade to the patched release most closely related to your current version of BIND 9: 9.20.29, 9.21.26, or 9.20.29-S1.


Workaround

No workarounds known.

History

Wed, 16 Sep 2026 14:30:00 +0000

Type Values Removed Values Added
Description A validly signed NSEC3 from an unrelated sibling zone may be accepted as an insecurity proof, downgrading a secure delegation and letting a forged unsigned answer through. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.
Title NSEC3 insecure-referral proof can use unrelated cached NSEC3 RRsets
First Time appeared Isc
Isc bind
Weaknesses CWE-346
CPEs cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
Vendors & Products Isc
Isc bind
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: isc

Published:

Updated: 2026-09-16T14:17:11.956Z

Reserved: 2026-08-20T12:48:33.514Z

Link: CVE-2026-77119

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-16T15:17:46.427

Modified: 2026-09-16T15:17:46.427

Link: CVE-2026-77119

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses