Insufficient verification of data authenticity in Unbound - CVE-2026-42960

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Main Vulnerability Database Vulnerabilities #VU131931

Insufficient verification of data authenticity in Unbound - CVE-2026-42960

Published: May 20, 2026


Vulnerability identifier: #VU131931
CSH Severity: Medium
CVSS v4: 8.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-42960
CWE-ID: CWE-345
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to poison Unbound's DNS cache.

The vulnerability exists due to improper cache validation in processing authority and additional section RRSets when handling spoofed DNS replies or fragmented responses. A remote attacker can inject non-NS RRSets accompanied by related address records to poison Unbound's DNS cache.

Exploitation requires the ability to attach malicious records to a reply, such as through packet spoofing or fragmentation attacks.


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 LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Micro
FreeBSD
Ubuntu
SUSE Package Hub 15
Basesystem Module
openSUSE Leap
openEuler
Anolis OS
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-utils
libunbound8
libunbound8-debuginfo
unbound-anchor-debuginfo
libunbound-devel-mini-debuginfo
unbound-munin
unbound-python
libunbound-devel-mini
libunbound-devel-mini-debugsource
unbound-python-debuginfo
unbound (Debian package)

How to mitigate CVE-2026-42960

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
python3-unbound - update to 1.17.1-11
unbound - update to 1.17.1-11
unbound-utils - update to 1.17.1-11
unbound-libs - update to 1.17.1-11
unbound-devel - update to 1.17.1-11
unbound-anchor - update to 1.17.1-11
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
libunbound-devel-mini-debuginfo - 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
unbound-python - 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

External References

Related Security Bulletins