Improper Check for Unusual or Exceptional Conditions in ISC BIND - CVE-2026-12617

Vulnerability identifier: #VU139208

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-12617

CWE-ID: CWE-754

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper handling of record ordering and response content in named resolver processing when processing responses to queries for CNAME or DNAME and A records. A remote attacker can send specially crafted DNS responses to cause a denial of service.

The issue is triggered when an authoritative server returns responses in a specific order, including delayed negative DNAME replies or a delayed self-referential CNAME reply.

ISC BIND
SUSE Linux Enterprise Server 15 SP6
Debian Linux
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
Basesystem Module
Server Applications Module
openSUSE Leap
Ubuntu
Anolis OS
openEuler
Fedora
BIG-IP DNS
BIG-IP
bind-debugsource
bind
bind-chroot
bind-debuginfo
bind-devel
bind-dnssec-utils
bind-libs
bind-utils
bind-dnssec-doc
bind-license
bind9 (Ubuntu package)
bind-doc
bind-utils-debuginfo
bind9 (Debian package)

Install security update from vendor's website.

ISC BIND - addressed in versions 9.20.26, 9.20.26-s1
bind-debugsource - addressed in versions 9.18.21-11, 9.20.21-4
bind - addressed in versions 9.18.21-11, 9.20.21-4
bind-chroot - addressed in versions 9.18.21-11, 9.20.21-4
bind-debuginfo - addressed in versions 9.18.21-11, 9.20.21-4
bind-devel - addressed in versions 9.18.21-11, 9.20.21-4
bind-dnssec-utils - addressed in versions 9.18.21-11, 9.20.21-4
bind-libs - addressed in versions 9.18.21-11, 9.20.21-4
bind-utils - addressed in versions 9.18.21-11, 9.20.21-4
bind-dnssec-doc - addressed in versions 9.18.21-11, 9.20.21-4
bind-license - addressed in versions 9.18.21-11, 9.20.21-4
bind9 (Ubuntu package) - addressed in versions 1:9.18.39-0ubuntu0.22.04.5, 1:9.18.39-0ubuntu0.24.04.6, 1:9.20.24-1ubuntu0.2
bind - addressed in versions 9.18.50-2.fc43, 9.18.50-2.fc44, 9.18.50-34.fc45
bind-doc - addressed in versions 9.18.50-150600.3.32.1, 9.20.26-150700.3.29.1
bind-utils-debuginfo - addressed in versions 9.18.50-150600.3.32.1, 9.20.26-150700.3.29.1
bind-debugsource - addressed in versions 9.18.50-150600.3.32.1, 9.20.26-150700.3.29.1
bind - addressed in versions 9.18.50-150600.3.32.1, 9.20.26-150700.3.29.1
bind-debuginfo - addressed in versions 9.18.50-150600.3.32.1, 9.20.26-150700.3.29.1
bind-utils - addressed in versions 9.18.50-150600.3.32.1, 9.20.26-150700.3.29.1
bind-devel - update to 9.20.26-1
bind-license - update to 9.20.26-1
bind-doc - update to 9.20.26-1
bind-dnssec-doc - update to 9.20.26-1
bind-utils - update to 9.20.26-1
bind-libs - update to 9.20.26-1
bind-dnssec-utils - update to 9.20.26-1
bind-chroot - update to 9.20.26-1
bind - update to 9.20.26-1
bind9 (Debian package) - update to 1:9.20.26-1~deb13u1

• https://kb.isc.org/docs/cve-2026-12617-record-ordering-based-unexpected-exit-with-cname-or-dname
• https://kb.isc.org/docs/cve-2026-12617

• Multiple vulnerabilities in ISC BIND
• Debian update for bind9
• SUSE update for bind
• SUSE update for bind
• openEuler 24.03 LTS SP1 update for bind
• openEuler 24.03 LTS SP4 update for bind
• openEuler 24.03 LTS SP3 update for bind
• Anolis OS update for bind
• Ubuntu update for bind9
• Fedora 45 update for bind
• Fedora 44 update for bind
• Fedora 43 update for bind
• Remote denial of service in BIG-IP DNS