CVE-2026-19941

checkwildcard() accepts an out-of-zone NSEC as a wildcard-nonexistence proof

Published Sep 16, 2026 CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed
Description
An inapplicable NSEC record may be accepted by a `named` resolver as proof that no wildcard exists, which could allow an attacker at the same or an upstream level of the zone name to mask the existence of a victim's wildcard record.
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.

Remediation

Vendor 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.


Vendor Workaround

No workarounds known.

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Debian DLA Debian DLA DLA-4865-1 bind9 security update
Ubuntu USN Ubuntu USN USN-8929-1 Bind vulnerabilities
Ubuntu USN Ubuntu USN USN-8969-1 Bind vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description An inapplicable NSEC record may be accepted by a `named` resolver as proof that no wildcard exists, which could allow an attacker at the same or an upstream level of the zone name to mask the existence of a victim's wildcard record. 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 checkwildcard() accepts an out-of-zone NSEC as a wildcard-nonexistence proof
First Time appeared Isc
Isc bind
Weaknesses CWE-345
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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
isc
Published
Updated
Sep 17, 2026, 6:44 PM
Reserved
Aug 15, 2026, 2:30 PM
Status
Awaiting Analysis
Published
Sep 16, 2026, 2:17 PM
Modified
Oct 26, 2026, 9:10 PM
Severity
Moderate
Public date
Sep 16, 2026, 1:52 PM