Resource exhaustion in Unbound - CVE-2026-41292

CSH
CYBERSECURITY HELP
Sign In REGISTER
 
Main Vulnerability Database Vulnerabilities #VU131926

Resource exhaustion in Unbound - CVE-2026-41292

Published: May 20, 2026


Vulnerability identifier: #VU131926
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-2026-41292
CWE-ID: CWE-400
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 uncontrolled resource consumption in EDNS option parsing when handling queries with long lists of EDNS options. A remote attacker can send specially crafted queries with too many EDNS options to cause a denial of service.

Coordinated attacks can degrade service by tying up Unbound threads while internal data structures for the options are being created.


Affected software

Unbound
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
Debian Linux
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Micro
Anolis OS
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
FreeBSD
Ubuntu
SUSE Package Hub 15
Basesystem Module
openSUSE Leap
openEuler
Fedora
LANTIME Operating System Firmware (LTOS)
unbound (Ubuntu package)
unbound-libs
unbound-help
unbound-devel
unbound-debugsource
unbound-debuginfo
python3-unbound
unbound
unbound-anchor
unbound (Red Hat package)
unbound-utils
libunbound8
libunbound8-debuginfo
unbound-anchor-debuginfo
unbound-python
unbound-munin
libunbound-devel-mini-debuginfo
libunbound-devel-mini
libunbound-devel-mini-debugsource
unbound-python-debuginfo
unbound (Debian package)

How to mitigate CVE-2026-41292

Install security update from vendor's website.

Unbound - update to 1.25.1
LANTIME Operating System Firmware (LTOS) - update to 7.10.012
unbound (Ubuntu package) - addressed in versions 1.4.22-1ubuntu4.14.04.3+esm3, 1.5.8-1ubuntu1.1+esm3, 1.6.7-1ubuntu2.6+esm4, 1.9.4-2ubuntu1.11+esm1, 1.13.1-1ubuntu5.15, 1.19.2-1ubuntu3.8, 1.22.0-2ubuntu2.3, 1.24.2-1ubuntu2.1
unbound-libs - addressed in versions 1.11.0-22, 1.13.2-22, 1.17.1-16
unbound-help - addressed in versions 1.11.0-22, 1.13.2-22, 1.17.1-16
unbound-devel - addressed in versions 1.11.0-22, 1.13.2-22, 1.17.1-16
unbound-debugsource - addressed in versions 1.11.0-22, 1.13.2-22, 1.17.1-16
unbound-debuginfo - addressed in versions 1.11.0-22, 1.13.2-22, 1.17.1-16
python3-unbound - addressed in versions 1.11.0-22, 1.13.2-22, 1.17.1-16
unbound - addressed in versions 1.11.0-22, 1.13.2-22, 1.17.1-16
unbound-anchor - addressed in versions 1.13.2-22, 1.17.1-16
unbound (Red Hat package) - addressed in versions 1.16.2-5.12.el8_10, 1.24.2-3.el9_8.2, 1.24.2-7.el10_2.2
unbound-libs - update to 1.16.2-9.0.2
unbound-devel - update to 1.16.2-9.0.2
unbound - update to 1.16.2-9.0.2
python3-unbound - update to 1.16.2-9.0.2
unbound-utils - update to 1.17.1-16
unbound-devel - addressed in versions 1.20.0-150100.10.25.1, 1.20.0-150600.23.16.1
unbound-debuginfo - addressed in versions 1.20.0-150100.10.25.1, 1.20.0-150600.23.16.1
libunbound8 - addressed in versions 1.20.0-150100.10.25.1, 1.20.0-150600.23.16.1
unbound-debugsource - addressed in versions 1.20.0-150100.10.25.1, 1.20.0-150600.23.16.1
unbound-anchor - addressed in versions 1.20.0-150100.10.25.1, 1.20.0-150600.23.16.1
libunbound8-debuginfo - addressed in versions 1.20.0-150100.10.25.1, 1.20.0-150600.23.16.1
unbound-anchor-debuginfo - addressed in versions 1.20.0-150100.10.25.1, 1.20.0-150600.23.16.1
unbound-python - update to 1.20.0-150600.23.16.1
unbound-munin - update to 1.20.0-150600.23.16.1
unbound - update to 1.20.0-150600.23.16.1
libunbound-devel-mini-debuginfo - update to 1.20.0-150600.23.16.1
libunbound-devel-mini - update to 1.20.0-150600.23.16.1
libunbound-devel-mini-debugsource - update to 1.20.0-150600.23.16.1
unbound-python-debuginfo - update to 1.20.0-150600.23.16.1
unbound (Debian package) - update to 1.22.0-2+deb13u3
unbound - addressed in versions 1.25.1-1.fc43, 1.25.1-1.fc44, 1.25.2-1.fc43

External References

Related Security Bulletins