Description
A DNSSEC validating resolver that is under a random subdomain attack against a DNSSEC-signed zone can suffer from runaway memory usage. The attacker needs to be able to send queries faster than the resolver can perform validation. The increased memory usage can be orders of magnitude beyond the limit configured in the `max-cache-size` parameter.
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| ISC | BIND 9 | 9.11.0 – ≤ 9.18.50, 9.20.0 – ≤ 9.20.24, 9.21.0 – ≤ 9.21.23, 9.11.3-S1 – ≤ 9.18.50-S1, 9.20.9-S1 – ≤ 9.20.24-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.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | bind9 | 1:9.20.26-1 | — |
| Debian 13 | bind9 | 1:9.20.26-1~deb13u1 | — |
| Debian 12 | bind9 | 1:9.18.49-1~deb12u2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | bind9 | 1:9.20.24-1ubuntu0.2 | USN-8929-1, USN-8648-1 |
| Ubuntu 26.04 LTS | isc-dhcp | No fix yet | — |
| Ubuntu 24.04 LTS | bind9 | 1:9.18.39-0ubuntu0.24.04.6 | USN-8929-1, USN-8648-1 |
| Ubuntu 24.04 LTS | isc-dhcp | No fix yet | — |
| Ubuntu 22.04 LTS | bind9 | 1:9.18.39-0ubuntu0.22.04.5 | USN-8929-1, USN-8648-1 |
| Ubuntu 22.04 LTS | bind9-libs | No fix yet | — |
| Ubuntu 20.04 LTS | bind9-libs | No fix yet | — |
| Ubuntu 18.04 LTS | isc-dhcp | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| 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 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | bind +7 | 32:9.18.33-15.el10_2.10 | RHSA-2026:55437 |
| RHEL 9 | bind +9 | 32:9.16.23-40.el9_8.8 | RHSA-2026:54510 |
| RHEL 9 | bind9.18 +6 | 32:9.18.29-14.el9_8.8 | RHSA-2026:55442 |
| RHEL 8 | bind +16 | 32:9.11.36-16.el8_10.14 | RHSA-2026:54654 |
| RHEL 8 | bind9.16 +8 | 32:9.16.23-0.22.el8_10.12 | RHSA-2026:54509 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9.6 EUS | bind +3 | 32:9.16.23-31.el9_6.4 | RHSA-2026:55441 |
| RHEL 9.4 E4S | bind +7 | 32:9.16.23-18.el9_4.12 | RHSA-2026:57189 |
| RHEL 8.8 TUS | bind9.16 +2 | 32:9.16.23-0.14.el8_8.9 | RHSA-2026:79160 |
| RHEL 8.8 E4S | bind9.16 +2 | 32:9.16.23-0.14.el8_8.9 | RHSA-2026:79160 |
| RHEL 8.6 EUS Long Life | bind9.16 +1 | 32:9.16.23-0.7.el8_6.11 | RHSA-2026:80501 |
| RHEL 8.6 AUS | bind9.16 +1 | 32:9.16.23-0.7.el8_6.11 | RHSA-2026:80501 |
| RHEL 7 ELS | bind +6 | 32:9.11.4-26.P2.el7_9.21 | RHSA-2026:60383 |
| Red Hat Hardened Images 1 | bind +6 | 9.20.26-0.1.hum1 | RHSA-2026:54071 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | bind +7 | 32:9.18.33-15.el10_2.10 | ALSA-2026:55437 |
| AlmaLinux 9 | bind +9 | 32:9.16.23-40.el9_8.8 | ALSA-2026:54510 |
| AlmaLinux 9 | bind9.18 +6 | 32:9.18.29-14.el9_8.8 | ALSA-2026:55442 |
| AlmaLinux 8 | bind +16 | 32:9.11.36-16.el8_10.14 | ALSA-2026:54654 |
| AlmaLinux 8 | bind9.16 +8 | 32:9.16.23-0.22.el8_10.12 | ALSA-2026:54509 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | bind | 2:9.18.33-15.el10_2.10 | RLSA-2026:55437 |
| Rocky Linux 9 | bind | 2:9.16.23-40.el9_8.8 | RLSA-2026:54510 |
| Rocky Linux 9 | bind9.18 | 2:9.18.29-14.el9_8.8 | RLSA-2026:55442 |
| Rocky Linux 8 | bind | 2:9.11.36-16.el8_10.14 | RLSA-2026:54654 |
| Rocky Linux 8 | bind9.16 | 2:9.16.23-0.22.el8_10.12 | RLSA-2026:54509 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | bind | 9.16.6-150300.22.62.1 | SUSE-SU-2026:3554-1, SUSE-SU-2026:3426-1 |
| SLES 15 SP6 | bind | 9.16.6-150300.22.62.1 | SUSE-SU-2026:3554-1, SUSE-SU-2026:3452-1 |
| SLES 15 SP5 | bind | 9.16.50-150500.8.41.1 | SUSE-SU-2026:3477-1 |
| SLES 15 SP4 | bind | 9.16.50-150400.5.65.1 | SUSE-SU-2026:3476-1 |
| SLES 12 SP5 | bind | 9.11.22-3.74.1 | SUSE-SU-2026:3484-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP6 | bind | 9.16.6-150300.22.62.1 | SUSE-SU-2026:3554-1, SUSE-SU-2026:3452-1 |
| SLES for SAP 15 SP5 | bind | 9.16.50-150500.8.41.1 | SUSE-SU-2026:3477-1 |
| SLES for SAP 15 SP4 | bind | 9.16.50-150400.5.65.1 | SUSE-SU-2026:3476-1 |
| SLE Micro 5.5 | bind | 9.16.50-150500.8.41.1 | SUSE-SU-2026:3477-1 |
| SLE HPC 15 SP5 | bind | 9.16.50-150500.8.41.1 | SUSE-SU-2026:3477-1 |
| SLE HPC 15 SP4 | bind | 9.16.50-150400.5.65.1 | SUSE-SU-2026:3476-1 |
| SUSE Multi Linux Manager Tools SLE-Micro-5 | bind | 9.16.6-150000.12.91.1 | SUSE-SU-2026:3517-1 |
| SUSE Manager Client Tools for SLE Micro 5 | bind | 9.16.6-150000.12.91.1 | SUSE-SU-2026:3517-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | bind | 9.20.26-1.1 | openSUSE-SU-2026:11375-1 |
| openSUSE Leap 16.0 | bind | 9.20.26-160000.1.1 | openSUSE-SU-2026:21489-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | bind | 9.20.26-r0 | — |
| Alpine v3.23 | bind | 9.20.26-r0 | — |
| Alpine v3.22 | bind | 9.20.26-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | bind +7 | 32:9.18.50-1.amzn2023.0.2 | ALAS2023-2026-2040 |
| Amazon Linux 2 | bind +15 | 32:9.11.4-26.P2.amzn2.13.17 | ALAS2-2026-3854 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | bind | 9.20.26-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | bind +7 | 32:9.18.33-15.0.1.el10_2.10 | ELSA-2026-55437 |
| Oracle Linux 9 | bind +9 | 32:9.16.23-40.0.1.el9_8.8 | ELSA-2026-54510 |
| Oracle Linux 9 | bind9.18 +6 | 32:9.18.29-14.el9_8.8 | ELSA-2026-55442 |
| Oracle Linux 8 | bind +16 | 32:9.11.36-16.el8_10.14 | ELSA-2026-54654 |
| Oracle Linux 8 | bind9.16 +8 | 32:9.16.23-0.22.el8_10.12 | ELSA-2026-54509 |
Advisories 42
- WID-SEC-2026-2484 Internet Systems Consortium BIND: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 5, 2026
- WID-SEC-2026-3595 IBM QRadar SIEM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 2, 2026
- ALSA-2026:54510 Important: bind security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:55442 Important: bind9.18 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:55437 Important: bind security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:54654 Important: bind security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:54509 Important: bind9.16 security update AlmaLinux Security Advisories · Oct 29, 2026
- USN-8929-1 bind9 vulnerabilities Ubuntu Security Notices (USN) · Oct 17, 2026
- RHSA-2026:80501 Red Hat Security Advisory: bind9.16 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:79160 Red Hat Security Advisory: bind9.16 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:57189 Red Hat Security Advisory: bind security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:55441 Red Hat Security Advisory: bind security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:55442 Red Hat Security Advisory: bind9.18 security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:55437 Red Hat Security Advisory: bind security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:54510 Red Hat Security Advisory: bind security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:54509 Red Hat Security Advisory: bind9.16 security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:54071 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:60383 Red Hat Security Advisory: bind security update Red Hat Security Advisories (RHSA) · Oct 12, 2026
- RHSA-2026:54654 Red Hat Security Advisory: bind security update Red Hat Security Advisories (RHSA) · Oct 12, 2026
- WID-SEC-2026-3038 Meinberg LANTIME: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 26, 2026
- USN-8648-1 bind9 vulnerabilities Ubuntu Security Notices (USN) · Aug 19, 2026
- RLSA-2026:55442 Important: bind9.18 security update Rocky Linux Security Advisories · Aug 17, 2026
- RLSA-2026:55437 Important: bind security update Rocky Linux Security Advisories · Aug 17, 2026
- ELSA-2026-55437 Important: bind security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Aug 17, 2026
- ELSA-2026-55442 Important: bind9.18 security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Aug 17, 2026
- RLSA-2026:54654 Important: bind security update Rocky Linux Security Advisories · Aug 15, 2026
- RLSA-2026:54510 Important: bind security update Rocky Linux Security Advisories · Aug 14, 2026
- RLSA-2026:54509 Important: bind9.16 security update Rocky Linux Security Advisories · Aug 14, 2026
- ELSA-2026-54510 Important: bind security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Aug 13, 2026
- ELSA-2026-54654 Important: bind security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Aug 13, 2026
- ELSA-2026-54509 Important: bind9.16 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Aug 13, 2026
- SUSE-SU-2026:3554-1 Security update for bind SUSE / openSUSE Security Updates · Aug 12, 2026
- SUSE-SU-2026:3517-1 Security update for bind SUSE / openSUSE Security Updates · Aug 7, 2026
- SUSE-SU-2026:3484-1 Security update for bind SUSE / openSUSE Security Updates · Aug 4, 2026
- ALAS2-2026-3854 Important: bind security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Aug 4, 2026
- SUSE-SU-2026:3477-1 Security update for bind SUSE / openSUSE Security Updates · Aug 4, 2026
- SUSE-SU-2026:3452-1 Security update for bind SUSE / openSUSE Security Updates · Aug 4, 2026
- SUSE-SU-2026:3476-1 Security update for bind SUSE / openSUSE Security Updates · Aug 4, 2026
- ALAS2023-2026-2040 Important: bind security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Aug 4, 2026
- openSUSE-SU-2026:21489-1 Security update for bind SUSE / openSUSE Security Updates · Jul 31, 2026
- SUSE-SU-2026:3426-1 Security update for bind SUSE / openSUSE Security Updates · Jul 31, 2026
- openSUSE-SU-2026:11375-1 bind-9.20.26-1.1 on GA media SUSE / openSUSE Security Updates · Jul 27, 2026
References
- CVE-2026-11622 vendor-advisory
- https://downloads.isc.org/isc/bind9/9.20.26 patch
- https://downloads.isc.org/isc/bind9/9.21.24 patch