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[USN-8648-1] Bind vulnerabilities

Posted on 19 August 2026
Ubuntu Security

==========================================================================Ubuntu Security Notice USN-8648-1
August 19, 2026

bind9 vulnerabilities
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 26.04 LTS
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS

Summary:

Several security issues were fixed in Bind.

Software Description:
- bind9: Internet Domain Name Server

Details:

It was discovered that Bind incorrectly accepted NSEC3 records whose signer
name did not match the owning zone. A remote attacker could possibly use
this issue to perform NSEC3 impersonation attacks, bypassing DNSSEC
validation. (CVE-2026-10723)

It was discovered that Bind incorrectly handled Key Records using the
PRIVATEDNS algorithm. A remote attacker could possibly use this issue to
cause Bind to crash, resulting in a denial of service. (CVE-2026-10822)

It was discovered that Bind incorrectly handled wildcard CNAME expansion in
Response Policy Zones. A remote attacker could possibly use this issue to
bypass configured RPZ policies. (CVE-2026-11331)

It was discovered that Bind performed unnecessary validation of DNSSEC
signed records. A remote attacker could possibly use this issue to cause
Bind to use excessive resources, leading to a denial of service. This issue
only affected Ubuntu 26.04 LTS. (CVE-2026-11605)

It was discovered that Bind incorrectly tracked memory usage in the DNS
cache. A remote attacker could possibly use this issue to cause Bind to use
memory beyond configured limits, leading to a denial of service.
(CVE-2026-11622)

It was discovered that Bind incorrectly handled signed wildcard records
with label count discrepancies and RRSIG validation. A remote attacker
could possibly use this issue to perform cache poisoning attacks.
(CVE-2026-11721)

It was discovered that Bind incorrectly handled certain CNAME and DNAME
record orderings in the resolver. A remote attacker could possibly use this
issue to cause Bind to crash, resulting in a denial of service.
(CVE-2026-12617)

It was discovered that Bind incorrectly validated out-of-zone NSEC next
owner names during DNSSEC validation. A remote attacker could possibly use
this issue to bypass DNSSEC validation. (CVE-2026-13321)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 26.04 LTS
bind9 1:9.20.24-1ubuntu0.2

Ubuntu 24.04 LTS
bind9 1:9.18.39-0ubuntu0.24.04.6

Ubuntu 22.04 LTS
bind9 1:9.18.39-0ubuntu0.22.04.5

In general, a standard system update will make all the necessary changes.

References:
https://ubuntu.com/security/notices/USN-8648-1
CVE-2026-10723, CVE-2026-10822, CVE-2026-11331, CVE-2026-11605,
CVE-2026-11622, CVE-2026-11721, CVE-2026-12617, CVE-2026-13321

Package Information:
https://launchpad.net/ubuntu/+source/bind9/1:9.20.24-1ubuntu0.2
https://launchpad.net/ubuntu/+source/bind9/1:9.18.39-0ubuntu0.24.04.6
https://launchpad.net/ubuntu/+source/bind9/1:9.18.39-0ubuntu0.22.04.5

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