USN-7855-2: Unbound regression

USN-7855-2: Unbound regression

Publication date: 2 December 2025
Overview: USN-7855-1 introduced a regression in Unbound

Packages
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
In general, a standard system update will make all the necessary changes.

The problem can be corrected by updating your system to the following package versions:

25.10 questing

• libunbound8 – 1.22.0-2ubuntu2.2
• unbound – 1.22.0-2ubuntu2.2

25.04 plucky

• libunbound8 – 1.22.0-1ubuntu1.3
• unbound – 1.22.0-1ubuntu1.3

24.04 LTS noble

• libunbound8 – 1.19.2-1ubuntu3.7
• unbound – 1.19.2-1ubuntu3.7

22.04 LTS jammy

• libunbound8 – 1.13.1-1ubuntu5.14
• unbound – 1.13.1-1ubuntu5.14