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Fencer Intel
high 7.5

CVE-2026-11721 json

Cache poisoning possible with label count discrepancy, RRSIG, and wildcards

published 3mo ago modified 7d ago also EUVD-2026-47709

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained. This causes `named` to produce a wildcard name for a zone that is shorter than the attacker's zone, which can result in cache poisoning. For this attack to have any effect, the resolver under attack must have set `synth-from-dnssec yes;` (which is the default). This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.

Patch / fix

  • isc bind 9.20.26, 9.21.24
  • bind9 Debian 12 1:9.18.49-1~deb12u2
  • bind9 Debian 13 1:9.20.26-1~deb13u1
  • bind9 Debian 14 1:9.20.26-1

debian advisories DEBIAN-CVE-2026-11721

  • bind9 Ubuntu 22.04 LTS 1:9.18.39-0ubuntu0.22.04.5
  • bind9 Ubuntu 24.04 LTS 1:9.18.39-0ubuntu0.24.04.6
  • bind9 Ubuntu 26.04 LTS 1:9.20.24-1ubuntu0.2
  • bind9 Ubuntu Pro 14.04 LTS 1:9.9.5.dfsg-3ubuntu0.19+esm15
  • bind9 Ubuntu Pro 16.04 LTS 1:9.10.3.dfsg.P4-8ubuntu1.19+esm11
  • bind9 Ubuntu Pro 18.04 LTS 1:9.11.3+dfsg-1ubuntu1.19+esm6
  • bind9 Ubuntu Pro 20.04 LTS 1:9.18.30-0ubuntu0.20.04.2+esm3

ubuntu advisories UBUNTU-CVE-2026-11721

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • bind9.18 RHEL 9 32:9.18.29-14.el9_8.8
  • bind9.18-libs RHEL 9 32:9.18.29-14.el9_8.8
  • bind9.18-utils RHEL 9 32:9.18.29-14.el9_8.8
  • bind9.18-chroot RHEL 9 32:9.18.29-14.el9_8.8
  • bind9.18-dnssec-utils RHEL 9 32:9.18.29-14.el9_8.8
  • bind RHEL 10.2 32:9.18.33-15.el10_2.10
  • bind-libs RHEL 10.2 32:9.18.33-15.el10_2.10
  • bind-utils RHEL 10.2 32:9.18.33-15.el10_2.10

red hat advisories RHSA-2026:80501RHSA-2026:79160RHSA-2026:60383RHSA-2026:57189RHSA-2026:55441RHSA-2026:55442

  • bind SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 9.16.6-150300.22.62.1
  • bind Multi Linux Manager Tools SLE-Micro-5, Manager Client Tools for SLE Micro 5 9.16.6-150000.12.91.1
  • bind SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 9.16.50-150500.8.41.1
  • bind SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 9.16.50-150400.5.65.1
  • bind SLE Module for Server Applications 15 SP7, SLE Module for Basesystem 15 SP7 9.20.26-150700.3.29.1
  • bind SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 9.11.22-3.74.1
  • bind SLES for SAP 15 SP6, SLES 15 SP6-LTSS 9.18.50-150600.3.32.1

suse advisories SUSE-SU-2026:3554-1SUSE-SU-2026:3517-1SUSE-SU-2026:3484-1SUSE-SU-2026:3477-1SUSE-SU-2026:3476-1SUSE-SU-2026:3452-1

  • bind openSUSE Leap 16.0 9.20.26-160000.1.1
  • bind openSUSE Tumbleweed 9.20.26-1.1

opensuse advisories openSUSE-SU-2026:21489-1openSUSE-SU-2026:11375-1

  • bind AlmaLinux 10 32:9.18.33-15.el10_2.10
  • bind-libs AlmaLinux 10 32:9.18.33-15.el10_2.10
  • bind-utils AlmaLinux 10 32:9.18.33-15.el10_2.10
  • bind-chroot AlmaLinux 10 32:9.18.33-15.el10_2.10
  • bind-license AlmaLinux 10 32:9.18.33-15.el10_2.10
  • bind-dnssec-utils AlmaLinux 10 32:9.18.33-15.el10_2.10
  • bind9.18 AlmaLinux 9 32:9.18.29-14.el9_8.8
  • bind9.18-libs AlmaLinux 9 32:9.18.29-14.el9_8.8

almalinux advisories ALSA-2026:55437ALSA-2026:55442ALSA-2026:54509ALSA-2026:54510ALSA-2026:54654

  • bind Rocky Linux 10 2:9.18.33-15.el10_2.10
  • bind9.18 Rocky Linux 9 2:9.18.29-14.el9_8.8
  • bind Rocky Linux 8 2:9.11.36-16.el8_10.14
  • bind Rocky Linux 9 2:9.16.23-40.el9_8.8
  • bind9.16 Rocky Linux 8 2:9.16.23-0.22.el8_10.12

rocky linux advisories RLSA-2026:55437RLSA-2026:55442RLSA-2026:54654RLSA-2026:54510RLSA-2026:54509

  • bind Alpine 3.24, Alpine 3.23, Alpine 3.22 9.20.26-r0

alpine advisories ALPINE-CVE-2026-11721

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • bind Azure Linux 3.0 9.20.26-1

azure linux advisories AZL-93132

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2026-11721 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-11721 updated cvss 7.5

bind: bind9: Cache poisoning via label count discrepancy, RRSIG, wildcards

  • Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.6) bind-libs 9.16.23-31.el9_6.4, bind9.18-libs 9.18.29-4.el9_6.5
    fixed: vendor fix RHSA-2026:55441
  • Red Hat Enterprise Linux AppStream (v. 8) bind 9.11.36-16.el8_10.14, bind-sdb 9.11.36-16.el8_10.14, bind-libs 9.11.36-16.el8_10.14, bind-utils 9.11.36-16.el8_10.14, bind9.16 9.16.23-0.22.el8_10.12, bind-chroot 9.11.36-16.el8_10.14, +13 more
    fixed: vendor fix RHSA-2026:54654
  • Red Hat Enterprise Linux AppStream (v. 9) bind 9.16.23-40.el9_8.8, bind9.18 9.18.29-14.el9_8.8, bind-libs 9.16.23-40.el9_8.8, bind-utils 9.16.23-40.el9_8.8, bind-chroot 9.16.23-40.el9_8.8, bind-license 9.16.23-40.el9_8.8, +6 more
    fixed: vendor fix RHSA-2026:54510
  • Red Hat Enterprise Linux AppStream (v. 10) bind 9.18.33-15.el10_2.10, bind-libs 9.18.33-15.el10_2.10, bind-utils 9.18.33-15.el10_2.10, bind-chroot 9.18.33-15.el10_2.10, bind-license 9.18.33-15.el10_2.10, bind-dnssec-utils 9.18.33-15.el10_2.10
    fixed: vendor fix RHSA-2026:55437
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) bind 9.11.26-4.el8_4.10, bind-sdb 9.11.26-4.el8_4.10, bind-libs 9.11.26-4.el8_4.10, bind-utils 9.11.26-4.el8_4.10, bind-pkcs11 9.11.26-4.el8_4.10, bind-libs-lite 9.11.26-4.el8_4.10, +2 more
    fixed: vendor fix RHSA-2026:95477
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) bind-sdb 9.11.36-3.el8_6.13, bind-libs 9.11.36-3.el8_6.13, bind-utils 9.11.36-3.el8_6.13, bind9.16 9.16.23-0.7.el8_6.11, bind-chroot 9.11.36-3.el8_6.13, bind-pkcs11 9.11.36-3.el8_6.13, +7 more
    fixed: vendor fix RHSA-2026:95435
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) bind 9.11.36-8.el8_8.11, bind-sdb 9.11.36-8.el8_8.11, bind-utils 9.11.36-8.el8_8.11, bind9.16 9.16.23-0.14.el8_8.9, bind-pkcs11 9.11.36-8.el8_8.11, bind-libs-lite 9.11.36-8.el8_8.11, +4 more
    fixed: vendor fix RHSA-2026:95478
show 25 more
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) bind 9.16.23-11.el9_2.12, bind-libs 9.16.23-11.el9_2.12, bind-dnssec-utils 9.16.23-11.el9_2.12
    fixed: vendor fix RHSA-2026:95242
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) bind 9.16.23-18.el9_4.12, bind-libs 9.16.23-18.el9_4.12, bind-utils 9.16.23-18.el9_4.12, bind-chroot 9.16.23-18.el9_4.12, bind-license 9.16.23-18.el9_4.12, python3-bind 9.16.23-18.el9_4.12, +1 more
    fixed: vendor fix RHSA-2026:57189
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) bind 9.18.33-4.el10_0.6, bind-libs 9.18.33-4.el10_0.6, bind-dnssec-utils 9.18.33-4.el10_0.6
    fixed: vendor fix RHSA-2026:94115
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) bind 9.16.23-31.el9_6.4, bind9.18 9.18.29-4.el9_6.5, bind-libs 9.16.23-31.el9_6.4, bind-utils 9.16.23-31.el9_6.4, bind9.18-libs 9.18.29-4.el9_6.5, bind-dnssec-utils 9.16.23-31.el9_6.4, +1 more
    fixed: vendor fix RHSA-2026:55441
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) bind 9.11.26-4.el8_4.10, bind-sdb 9.11.26-4.el8_4.10, bind-libs 9.11.26-4.el8_4.10, bind-utils 9.11.26-4.el8_4.10, bind-pkcs11 9.11.26-4.el8_4.10, bind-libs-lite 9.11.26-4.el8_4.10, +2 more
    fixed: vendor fix RHSA-2026:95477
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) bind-sdb 9.11.36-3.el8_6.13, bind-libs 9.11.36-3.el8_6.13, bind-utils 9.11.36-3.el8_6.13, bind9.16 9.16.23-0.7.el8_6.11, bind-chroot 9.11.36-3.el8_6.13, bind-pkcs11 9.11.36-3.el8_6.13, +7 more
    fixed: vendor fix RHSA-2026:95435
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) bind 9.11.36-8.el8_8.11, bind-sdb 9.11.36-8.el8_8.11, bind-utils 9.11.36-8.el8_8.11, bind9.16 9.16.23-0.14.el8_8.9, bind-pkcs11 9.11.36-8.el8_8.11, bind-libs-lite 9.11.36-8.el8_8.11, +4 more
    fixed: vendor fix RHSA-2026:95478
  • Red Hat Enterprise Linux BaseOS (v. 8) bind 9.11.36-16.el8_10.14, bind-export-libs 9.11.36-16.el8_10.14
    fixed: vendor fix RHSA-2026:54654
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) bind 9.11.26-4.el8_4.10, bind-export-libs 9.11.26-4.el8_4.10
    fixed: vendor fix RHSA-2026:95477
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) bind-export-libs 9.11.36-3.el8_6.13
    fixed: vendor fix RHSA-2026:95435
  • Red Hat Enterprise Linux BaseOS E4S (v.8.8) bind 9.11.36-8.el8_8.11, bind-export-libs 9.11.36-8.el8_8.11
    fixed: vendor fix RHSA-2026:95478
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) bind 9.11.26-4.el8_4.10, bind-export-libs 9.11.26-4.el8_4.10
    fixed: vendor fix RHSA-2026:95477
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) bind-export-libs 9.11.36-3.el8_6.13
    fixed: vendor fix RHSA-2026:95435
  • Red Hat Enterprise Linux BaseOS TUS (v.8.8) bind 9.11.36-8.el8_8.11, bind-export-libs 9.11.36-8.el8_8.11
    fixed: vendor fix RHSA-2026:95478
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) bind-libs 9.16.23-40.el9_8.8, bind9.18-libs 9.18.29-14.el9_8.8
    fixed: vendor fix RHSA-2026:54510
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) bind-doc 9.18.33-15.el10_2.10, bind-devel 9.18.33-15.el10_2.10, bind-debuginfo 9.18.33-15.el10_2.10, bind-debugsource 9.18.33-15.el10_2.10, bind-libs-debuginfo 9.18.33-15.el10_2.10, bind-utils-debuginfo 9.18.33-15.el10_2.10, +1 more
    fixed: vendor fix RHSA-2026:55437
  • Red Hat Enterprise Linux CRB (v. 8) bind9.16-libs 9.16.23-0.22.el8_10.12
    fixed: vendor fix RHSA-2026:54509
  • Red Hat Enterprise Linux Server -EXTENSION(v. 6 ELS-EXTENSION) bind 9.8.2-0.68.rc1.el6_10.20, bind-libs 9.8.2-0.68.rc1.el6_10.20
    fixed: vendor fix RHSA-2026:95727
  • Red Hat Enterprise Linux Server (v. 7 ELS) bind 9.11.4-26.P2.el7_9.21, bind-libs-lite 9.11.4-26.P2.el7_9.21, bind-export-libs 9.11.4-26.P2.el7_9.21, bind-pkcs11-libs 9.11.4-26.P2.el7_9.21, bind-pkcs11-utils 9.11.4-26.P2.el7_9.21
    fixed: vendor fix RHSA-2026:60383
  • Red Hat Enterprise Linux Server Optional -EXTENSION (v. 6 ELS -EXTENSION) bind-sdb 9.8.2-0.68.rc1.el6_10.20
    fixed: vendor fix RHSA-2026:95727
  • Red Hat Hardened Images bind 9.20.26-0.1.hum1, bind-libs 9.20.26-0.1.hum1, bind-utils 9.20.26-0.1.hum1, bind-chroot 9.20.26-0.1.hum1, bind-dnssec-utils 9.20.26-0.1.hum1
    fixed: vendor fix RHSA-2026:54071
  • Red Hat OpenShift Container Platform 4.22 rhcos 4.22.9.8.202608191915, rhcos 4.22.9.8.202609081748
    fixed: vendor fix RHSA-2026:57362
  • Red Hat CodeReady Linux Builder EUS (v.9.6) bind-doc 9.16.23-31.el9_6.4, bind-devel 9.16.23-31.el9_6.4, bind9.18-doc 9.18.29-4.el9_6.5, bind9.18-devel 9.18.29-4.el9_6.5, bind-debuginfo 9.16.23-31.el9_6.4, bind-debugsource 9.16.23-31.el9_6.4, +8 more
    not affected: vulnerable code not present
  • Red Hat Enterprise Linux 9 dhcp, dhcp-relay, dhcp-client, dhcp-common, dhcp-server
    not affected: vulnerable code not in execute path
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) bind-chroot 9.11.26-4.el8_4.10, bind-license 9.11.26-4.el8_4.10, python3-bind 9.11.26-4.el8_4.10, bind-sdb-chroot 9.11.26-4.el8_4.10 Red Hat Enterprise Linux AppStream AUS (v.8.6) bind 9.11.36-3.el8_6.13, bind9.16-utils 9.16.23-0.7.el8_6.11, bind9.16-chroot 9.16.23-0.7.el8_6.11, bind9.16-license 9.16.23-0.7.el8_6.11 Red Hat Enterprise Linux AppStream E4S (v.8.8) bind-libs 9.11.36-8.el8_8.11, bind-chroot 9.11.36-8.el8_8.11, bind-license 9.11.36-8.el8_8.11, python3-bind 9.11.36-8.el8_8.11, bind-sdb-chroot 9.11.36-8.el8_8.11, bind9.16-utils 9.16.23-0.14.el8_8.9, +3 more Red Hat Enterprise Linux AppStream E4S (v.9.2) bind-utils 9.16.23-11.el9_2.12, bind-chroot 9.16.23-11.el9_2.12, bind-license 9.16.23-11.el9_2.12, python3-bind 9.16.23-11.el9_2.12 Red Hat Enterprise Linux AppStream EUS (v. 10.0) bind-utils 9.18.33-4.el10_0.6, bind-chroot 9.18.33-4.el10_0.6, bind-license 9.18.33-4.el10_0.6 Red Hat Enterprise Linux AppStream EUS (v.9.6) bind-chroot 9.16.23-31.el9_6.4, bind-license 9.16.23-31.el9_6.4, python3-bind 9.16.23-31.el9_6.4, bind9.18-utils 9.18.29-4.el9_6.5, bind9.18-chroot 9.18.29-4.el9_6.5
    +1 more products
    Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) bind-chroot 9.11.26-4.el8_4.10, bind-license 9.11.26-4.el8_4.10, python3-bind 9.11.26-4.el8_4.10, bind-sdb-chroot 9.11.26-4.el8_4.10
    not affected: vulnerable code not present

13 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
3mo ago

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

  • ISC BIND 9

Classification

Weakness
  • CWE-1284 Improper Validation of Specified Quantity in Input

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.