==========================================================================
Ubuntu Security Notice USN-7836-1
October 22, 2025

bind9 vulnerabilities
==========================================================================

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:

Several security issues were fixed in Bind.

Software Description:
- bind9: Internet Domain Name Server

Details:

Zuyao Xu and Xiang Li discovered that Bind incorrectly handled certain
malformed DNSKEY records. A remote attacker could possibly use this issue
to cause Bind to consume resources, resulting in a denial of service.
(CVE-2025-8677)

Yuxiao Wu, Yunyi Zhang, Baojun Liu, and Haixin Duan discovered that Bind
incorrectly accepted certain records from answers. A remote attacker could
possibly use this issue to perform a cache poisoning attack.
(CVE-2025-40778)

Amit Klein and Omer Ben Simhon discovered that Bind used a weak PRNG. A
remote attacker could possibly use this issue to perform a cache poisoning
attack. (CVE-2025-40780)

Update instructions:

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

Ubuntu 25.10
  bind9                           1:9.20.11-1ubuntu2.1

Ubuntu 25.04
  bind9                           1:9.20.11-0ubuntu0.2

Ubuntu 24.04 LTS
  bind9                           1:9.18.39-0ubuntu0.24.04.2

Ubuntu 22.04 LTS
  bind9                           1:9.18.39-0ubuntu0.22.04.2

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

References:
  https://ubuntu.com/security/notices/USN-7836-1
  CVE-2025-40778, CVE-2025-40780, CVE-2025-8677

Package Information:
  https://launchpad.net/ubuntu/+source/bind9/1:9.20.11-1ubuntu2.1
  https://launchpad.net/ubuntu/+source/bind9/1:9.20.11-0ubuntu0.2
  https://launchpad.net/ubuntu/+source/bind9/1:9.18.39-0ubuntu0.24.04.2
  https://launchpad.net/ubuntu/+source/bind9/1:9.18.39-0ubuntu0.22.04.2