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OpenAdvisories
Medium · 5.9 CVE-2026-19941 EUVD-2026-80745GHSA-38fx-cm5x-27pg

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

Published Sep 16, 2026 · Updated Sep 17, 2026 · Assigned by isc

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.

Affected products

VendorProductAffectedFixed
ISC BIND 9 9.11.0 – ≤ 9.18.50, 9.20.0 – ≤ 9.20.27, 9.21.0 – ≤ 9.21.25, 9.11.3-S1 – ≤ 9.18.50-S1, 9.20.9-S1 – ≤ 9.20.27-S1 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 bind9 1:9.20.29-1 —
Debian 13 bind9 1:9.20.29-1~deb13u1 —
Debian 12 bind9 1:9.18.49-1~deb12u3 —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 bind9 1:9.20.24-1ubuntu3.1 USN-8969-1
Ubuntu 26.04 LTS bind9 1:9.20.24-1ubuntu0.4 USN-8969-1, USN-8929-1
Ubuntu 26.04 LTS isc-dhcp No fix yet —
Ubuntu 24.04 LTS bind9 1:9.18.39-0ubuntu0.24.04.8 USN-8969-1, USN-8929-1
Ubuntu 24.04 LTS isc-dhcp No fix yet —
Ubuntu 22.04 LTS bind9 1:9.18.39-0ubuntu0.22.04.7 USN-8969-1, USN-8929-1
Ubuntu 22.04 LTS bind9-libs No fix yet —
Ubuntu 20.04 LTS bind9-libs No fix yet —
Show 5 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 18.04 LTS isc-dhcp No fix yet —
Ubuntu Pro 20.04 LTS bind9 1:9.18.30-0ubuntu0.20.04.2+esm3 USN-8929-1
Ubuntu Pro 18.04 LTS bind9 1:9.11.3+dfsg-1ubuntu1.19+esm6 USN-8929-1
Ubuntu Pro 16.04 LTS bind9 1:9.10.3.dfsg.P4-8ubuntu1.19+esm11 USN-8929-1
Ubuntu Pro 14.04 LTS bind9 1:9.9.5.dfsg-3ubuntu0.19+esm15 USN-8929-1
ReleasePackageFixed inAdvisory
Red Hat Hardened Images 1 bind +6 9.20.29-0.1.hum1 RHSA-2026:68279
ReleasePackageFixed inAdvisory
SLES 15 SP7 bind 9.20.29-150700.3.32.2 SUSE-SU-2026:4285-1
SLES 15 SP6 bind 9.18.50-150600.3.35.1 SUSE-SU-2026:4608-1
SLES 15 SP5 bind 9.16.50-150500.8.46.1 SUSE-SU-2026:4772-1
SLES 15 SP4 bind 9.16.50-150400.5.70.1 SUSE-SU-2026:4664-1
SLES 12 SP5 bind 9.11.22-3.77.1 SUSE-SU-2026:4635-1
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 bind 9.20.29-160000.1.1 SUSE-SU-2026:24157-1
SLES for SAP 15 SP6 bind 9.18.50-150600.3.35.1 SUSE-SU-2026:4608-1
SLES for SAP 15 SP5 bind 9.16.50-150500.8.46.1 SUSE-SU-2026:4772-1
SLES for SAP 15 SP4 bind 9.16.50-150400.5.70.1 SUSE-SU-2026:4664-1
SLES 16.0 bind 9.20.29-160000.1.1 SUSE-SU-2026:24157-1
SLE Micro 5.5 bind 9.16.50-150500.8.46.1 SUSE-SU-2026:4772-1
SLE HPC 15 SP5 bind 9.16.50-150500.8.46.1 SUSE-SU-2026:4772-1
SLE HPC 15 SP4 bind 9.16.50-150400.5.70.1 SUSE-SU-2026:4664-1
SUSE Multi Linux Manager Tools SLE-Micro-5 bind 9.16.6-150000.12.97.1 SUSE-SU-2026:5118-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed bind 9.20.29-1.1 openSUSE-SU-2026:11916-1
openSUSE Leap 16.0 bind 9.20.29-160000.1.1 openSUSE-SU-2026:22049-1
ReleasePackageFixed inAdvisory
Alpine v3.24 bind 9.20.29-r0 —
Alpine v3.23 bind 9.20.29-r0 —
Alpine v3.22 bind 9.20.29-r0 —

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 bind +7 32:9.18.50-1.amzn2023.0.3 ALAS2023-2026-3137
Amazon Linux 2 bind +15 32:9.11.4-26.P2.amzn2.13.18 ALAS2-2026-3995

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 bind 9.20.30-1 —

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling bind +2 9.20.30-r0 —
Wolfi rolling bind-libs +3 9.20.29-r1 —

Advisories 15

References