Description
The issue is a resource exhaustion vulnerability associated with DNSSEC validation. BIND always validates all RRSIG records in an answer, even if they are not strictly needed. A query to an authoritative server/zone which returns many valid but superfluous RRSIG records causes the validator to waste disproportionate CPU time.
This issue affects BIND 9 versions 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| ISC | BIND 9 | 9.20.0 – ≤ 9.20.24, 9.21.0 – ≤ 9.21.23, 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-8648-1 |
| Ubuntu 24.04 LTS | bind9 | 1:9.18.39-0ubuntu0.24.04.6 | USN-8648-1 |
| Ubuntu 22.04 LTS | bind9 | 1:9.18.39-0ubuntu0.22.04.5 | USN-8648-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | bind +6 | 32:9.18.50-22.hum1 | RHSA-2026:42853 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | bind | 9.20.26-150700.3.29.1 | SUSE-SU-2026:3426-1 |
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 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | bind | 9.20.26-1 | — |
Advisories 7
- RHSA-2026:42853 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- WID-SEC-2026-2484 Internet Systems Consortium BIND: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 5, 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
- 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-2026-11605 vendor-advisory
- https://downloads.isc.org/isc/bind9/9.20.26 patch
- https://downloads.isc.org/isc/bind9/9.21.24 patch