Insufficient verification of data authenticity in Unbound - CVE-2026-50248

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Main Vulnerability Database Vulnerabilities #VU139217

Insufficient verification of data authenticity in Unbound - CVE-2026-50248

Published: July 23, 2026


Vulnerability identifier: #VU139217
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-50248
CWE-ID: CWE-345
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to replace the entire zone data or the resolver's entire response policy.

The vulnerability exists due to improper validation of configured primary hostnames in auth/rpz zone XFR endpoint selection when resolving a configured primary hostname to BOGUS A/AAAA records. A remote attacker can spoof the hostname's A/AAAA record to replace the entire zone data or the resolver's entire response policy.

No valid RRSIG is required for exploitation.


Affected software

Unbound
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Micro
SUSE Package Hub 15
Basesystem Module
openSUSE Leap
openEuler
Fedora
unbound
python3-unbound
unbound-debuginfo
unbound-debugsource
unbound-devel
unbound-help
unbound-libs
unbound-anchor
unbound-utils
libunbound8
libunbound8-debuginfo
unbound-anchor-debuginfo
unbound-munin
unbound-python
unbound-python-debuginfo
libunbound-devel-mini-debuginfo
libunbound-devel-mini-debugsource
libunbound-devel-mini

How to mitigate CVE-2026-50248

Install security update from vendor's website.

Unbound - update to 1.25.2
unbound - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
python3-unbound - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-debuginfo - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-debugsource - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-devel - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-help - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-libs - addressed in versions 1.11.0-25, 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-anchor - addressed in versions 1.13.2-25, 1.17.1-19, 1.17.1-20
unbound-utils - addressed in versions 1.17.1-19, 1.17.1-20
unbound - update to 1.25.2-1.fc43
libunbound8 - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-devel - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
libunbound8-debuginfo - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-anchor - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-debugsource - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-anchor-debuginfo - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-debuginfo - addressed in versions 1.25.2-150100.10.28.1, 1.25.2-150600.23.19.1
unbound-munin - update to 1.25.2-150600.23.19.1
unbound-python - update to 1.25.2-150600.23.19.1
unbound - update to 1.25.2-150600.23.19.1
unbound-python-debuginfo - update to 1.25.2-150600.23.19.1
libunbound-devel-mini-debuginfo - update to 1.25.2-150600.23.19.1
libunbound-devel-mini-debugsource - update to 1.25.2-150600.23.19.1
libunbound-devel-mini - update to 1.25.2-150600.23.19.1

External References

Related Security Bulletins