Home / mailings [USN-7855-2] Unbound regression
Posted on 02 December 2025
Ubuntu Security==========================================================================Ubuntu Security Notice USN-7855-2
December 02, 2025
unbound regression
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 25.10
- Ubuntu 25.04
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
Summary:
USN-7855-1 introduced a regression in Unbound
Software Description:
- unbound: validating, recursive, caching DNS resolver
Details:
USN-7855-1 fixed vulnerabilities in Unbound. It was discovered that the fix
for CVE-2025-11411 was incomplete. This update fixes the problem.
Original advisory details:
Yuxiao Wu, Yunyi Zhang, Baojun Liu, and Haixin Duan discovered that
Unbound incorrectly handled certain promiscuous NS RRSets. A remote
attacker could possibly use this issue to perform a domain hijack attack.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 25.10
libunbound8 1.22.0-2ubuntu2.2
unbound 1.22.0-2ubuntu2.2
Ubuntu 25.04
libunbound8 1.22.0-1ubuntu1.3
unbound 1.22.0-1ubuntu1.3
Ubuntu 24.04 LTS
libunbound8 1.19.2-1ubuntu3.7
unbound 1.19.2-1ubuntu3.7
Ubuntu 22.04 LTS
libunbound8 1.13.1-1ubuntu5.14
unbound 1.13.1-1ubuntu5.14
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-7855-2
https://ubuntu.com/security/notices/USN-7855-1
CVE-2025-11411, https://launchpad.net/bugs/2133715
Package Information:
https://launchpad.net/ubuntu/+source/unbound/1.22.0-2ubuntu2.2
https://launchpad.net/ubuntu/+source/unbound/1.22.0-1ubuntu1.3
https://launchpad.net/ubuntu/+source/unbound/1.19.2-1ubuntu3.7
https://launchpad.net/ubuntu/+source/unbound/1.13.1-1ubuntu5.14
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