Memory leak in ISC BIND - CVE-2026-81563

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Main Vulnerability Database Vulnerabilities #VU150227

Memory leak in ISC BIND - CVE-2026-81563

Published: September 16, 2026


Vulnerability identifier: #VU150227
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-2026-81563
CWE-ID: CWE-401
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

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

The vulnerability exists due to a failure to properly deallocate internal resources in SVCB/HTTPS AliasMode additional-data processing when processing an SVCB/HTTPS AliasMode record that references 14 or more SVCB/HTTPS ServiceMode records. A remote attacker can cause the resolver to process such records to cause a denial of service.

Repeated exploitation is required to exhaust resources.


Affected software

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

How to mitigate CVE-2026-81563

Install security update from vendor's website.

ISC BIND - addressed in versions 9.20.29, 9.20.29-s1, 9.21.26
bind9 (Ubuntu package) - addressed in versions 1:9.9.5.dfsg-3ubuntu0.19+esm15, 1:9.10.3.dfsg.P4-8ubuntu1.19+esm11, 1:9.11.3+dfsg-1ubuntu1.19+esm6, 1:9.18.30-0ubuntu0.20.04.2+esm3, 1:9.18.39-0ubuntu0.22.04.7, 1:9.18.39-0ubuntu0.24.04.8, 1:9.20.24-1ubuntu0.4
bind-chroot - addressed in versions 9.18.21-14, 9.20.21-5
bind-dnssec-utils - addressed in versions 9.18.21-14, 9.20.21-5
bind-devel - addressed in versions 9.18.21-14, 9.20.21-5
bind-debugsource - addressed in versions 9.18.21-14, 9.20.21-5
bind-debuginfo - addressed in versions 9.18.21-14, 9.20.21-5
bind - addressed in versions 9.18.21-14, 9.20.21-5
bind-libs - addressed in versions 9.18.21-14, 9.20.21-5
bind-utils - addressed in versions 9.18.21-14, 9.20.21-5
bind-dnssec-doc - addressed in versions 9.18.21-14, 9.20.21-5
bind-license - addressed in versions 9.18.21-14, 9.20.21-5
bind - addressed in versions 9.18.51^git20261003.d0a87358-2.fc43, 9.18.51^git20261003.d0a87358-2.fc44, 9.18.51^git20261003.d0a87358-11.fc46
bind-utils - update to 9.20.29-1
bind-libs - update to 9.20.29-1
bind-dnssec-utils - update to 9.20.29-1
bind-devel - update to 9.20.29-1
bind-chroot - update to 9.20.29-1
bind - update to 9.20.29-1
bind-license - update to 9.20.29-1
bind-doc - update to 9.20.29-1
bind-dnssec-doc - update to 9.20.29-1
bind-utils - update to 9.20.29-150700.3.32.2
bind - update to 9.20.29-150700.3.32.2
bind-debugsource - update to 9.20.29-150700.3.32.2
bind-utils-debuginfo - update to 9.20.29-150700.3.32.2
bind-debuginfo - update to 9.20.29-150700.3.32.2
bind-doc - update to 9.20.29-150700.3.32.2
bind9-next - addressed in versions 9.21.26-1.fc43, 9.21.26-1.fc44, 9.21.26-1.fc45
bind-dyndb-ldap - addressed in versions 11.11-15.fc43, 11.11-17.fc44, 11.11-18.fc46
bind9 (Debian package) - update to 1:9.20.29-1~deb13u1

External References

Related Security Bulletins