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High USN-8648-1 8 CVEs

bind9 vulnerabilities

Published Aug 19, 2026 · Updated Aug 19, 2026

Ecosystem: Ubuntu

Summary

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)

Fixed packages 3

ReleasePackageFixed in
Ubuntu · 22.04 LTS 22.04:LTS bind9 1:9.18.39-0ubuntu0.22.04.5
Ubuntu · 24.04 LTS 24.04:LTS bind9 1:9.18.39-0ubuntu0.24.04.6
Ubuntu · 26.04 LTS 26.04:LTS bind9 1:9.20.24-1ubuntu0.2

Vulnerabilities 8

  • High 8.6
    CVE-2026-13321

    DNSSEC Validation Bypass via Out-of-Zone NSEC Next Field

    The BIND resolver accepts validly-signed NSEC records where the "Next Domain Name" field points outside the signer's zone. 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,…

    ISC BIND 9 bind9 bind9 Debian Ubuntu Azure Linux Alpine
  • High 7.5
    CVE-2026-11331

    Potential wildcard CNAME RPZ policy bypass

    An attacker who knows (or guesses) that a resolver uses RPZ with wildcard CNAME policies can craft query names long enough to trigger a NAMETOOLONG error condition during RPZ processing. This is not handled correctly and may lead to defeating the RPZ rule. It…

    ISC BIND 9 bind9 bind9 Debian Ubuntu Azure Linux Alpine
  • High 7.5
    CVE-2026-11605

    Unnecessary validation of DNSSEC signed records

    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 RR…

    ISC BIND 9 bind9 bind9 Debian Ubuntu Azure Linux Alpine
  • High 7.5
    CVE-2026-11622

    Potential memory usage beyond configured limits

    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 c…

    ISC BIND 9 bind9 bind9 Debian Ubuntu Azure Linux Alpine
  • High 7.5
    CVE-2026-11721

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

    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, wh…

    ISC BIND 9 bind9 bind9 Debian Ubuntu Azure Linux Alpine
  • High 7.5
    CVE-2026-12617

    Record ordering based unexpected exit with CNAME or DNAME

    The issue is unexpected program termination based on ordering and/or specific content in responses to queries for CNAME or DNAME, and A records. Specifically, if a client queries for a DNAME and A record below the DNAME to the resolver, and the authoritative …

    ISC BIND 9 bind9 bind9 Debian Ubuntu Azure Linux Alpine
  • Medium 6.8
    CVE-2026-10723

    Incorrect acceptance of NSEC3 records

    BIND may accept incorrect child-zone NSEC3 records as valid, which could allow an attacker to forge authenticated NXDOMAIN responses. This issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through …

    ISC BIND 9 bind9 bind9 Debian Ubuntu Azure Linux Alpine
  • Medium 6.5
    CVE-2026-10822

    Key Record using PRIVATEDNS algorithm may lead to unexpected exit

    If BIND encounters a particular invalid data structure in a DNS record, it will accept the invalid data, and may subsequently abort and exit. BIND will first need to store a DNS record for a key (KEY, DNSKEY, etc.). That key must specify a PRIVATEDNS algorith…

    ISC BIND 9 bind9 bind9 Debian Ubuntu Azure Linux Alpine

References

  • report
    https://ubuntu.com/security/CVE-2026-10723
  • report
    https://ubuntu.com/security/CVE-2026-10822
  • report
    https://ubuntu.com/security/CVE-2026-11331
  • report
    https://ubuntu.com/security/CVE-2026-11605
  • report
    https://ubuntu.com/security/CVE-2026-11622
  • report
    https://ubuntu.com/security/CVE-2026-11721
  • report
    https://ubuntu.com/security/CVE-2026-12617
  • report
    https://ubuntu.com/security/CVE-2026-13321