RHSA-2026:54509HighCVSS 8.6

Red Hat Security Advisory: bind9.16 security update

Published
August 13, 2026
Last Modified
October 16, 2026

🔗 CVE IDs covered (6)

CVE-2026-13204 →CVE-2026-13321 →CVE-2026-10723 →CVE-2026-11331 →CVE-2026-11622 →CVE-2026-11721 →

📋 Description

CVE-2026-10723 — bind: bind9: Incorrect acceptance of NSEC3 records CVE-2026-11331 — bind: bind: Denial of Service via long query names in RPZ processing CVE-2026-11622 — bind: bind9: Potential memory usage beyond configured limits CVE-2026-11721 — bind: bind9: Cache poisoning via label count discrepancy, RRSIG, wildcards CVE-2026-13204 — bind: bind9: Unexpected exit with NSEC and NSEC3 both present CVE-2026-13321 — bind: bind9: DNSSEC Validation Bypass via Out-of-Zone NSEC Next Field

🎯 Affected products77

  • Red Hat Enterprise Linux AppStream (v. 8)
  • Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-32:9.16.23-0.22.el8_10.12.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-32:9.16.23-0.22.el8_10.12.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-32:9.16.23-0.22.el8_10.12.s390x as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-32:9.16.23-0.22.el8_10.12.src as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-32:9.16.23-0.22.el8_10.12.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-chroot-32:9.16.23-0.22.el8_10.12.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-chroot-32:9.16.23-0.22.el8_10.12.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-chroot-32:9.16.23-0.22.el8_10.12.s390x as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-chroot-32:9.16.23-0.22.el8_10.12.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-debuginfo-32:9.16.23-0.22.el8_10.12.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-debuginfo-32:9.16.23-0.22.el8_10.12.aarch64 as a component of Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-debuginfo-32:9.16.23-0.22.el8_10.12.i686 as a component of Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-debuginfo-32:9.16.23-0.22.el8_10.12.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-debuginfo-32:9.16.23-0.22.el8_10.12.ppc64le as a component of Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-debuginfo-32:9.16.23-0.22.el8_10.12.s390x as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-debuginfo-32:9.16.23-0.22.el8_10.12.s390x as a component of Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-debuginfo-32:9.16.23-0.22.el8_10.12.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-debuginfo-32:9.16.23-0.22.el8_10.12.x86_64 as a component of Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-debugsource-32:9.16.23-0.22.el8_10.12.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-debugsource-32:9.16.23-0.22.el8_10.12.aarch64 as a component of Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-debugsource-32:9.16.23-0.22.el8_10.12.i686 as a component of Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-debugsource-32:9.16.23-0.22.el8_10.12.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-debugsource-32:9.16.23-0.22.el8_10.12.ppc64le as a component of Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-debugsource-32:9.16.23-0.22.el8_10.12.s390x as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-debugsource-32:9.16.23-0.22.el8_10.12.s390x as a component of Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-debugsource-32:9.16.23-0.22.el8_10.12.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 8)
  • bind9.16-debugsource-32:9.16.23-0.22.el8_10.12.x86_64 as a component of Red Hat Enterprise Linux CRB (v. 8)
  • bind9.16-devel-32:9.16.23-0.22.el8_10.12.aarch64 as a component of Red Hat Enterprise Linux CRB (v. 8)
  • +47 more not shown

✅ Remediation

For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Workaround: To mitigate this issue, restrict resolver access to trusted networks and avoid using wildcard CNAME entries within Response Policy Zones (RPZ). 1. Edit `/etc/named.conf` to limit recursion and query caching to authorized client networks: ``` acl trusted_clients { 127.0.0.1; 192.168.1.0/24; }; options { allow-recursion { trusted_clients; }; allow-query-cache { trusted_clients; }; }; ``` Additionally, modify RPZ zone files to remove wildcard CNAME statements (such as `*.example.com CNAME target.com`), replacing them with explicit individual domain entries where feasible. 2. Reload the named service configuration: `systemctl reload named` Caveats: Restricting query access prevents untrusted external clients from resolving names through the server. Removing wildcard entries means unlisted subdomains will no longer be intercepted by the policy zone until explicit records are added. Warning: Reloading or restarting the named daemon may briefly disrupt ongoing DNS resolution. Workaround: Disclaimer: The following mitigation notes are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure. ISC states no workarounds exist. Until patched, restrict the resolver to authorized client networks and deploy separate resolvers per trust zone. Memory hardening and auth controls don't apply — this is a DNS protocol logic error using validly-signed records.

🔗 References (9)