Ubuntu 25.10: Critical DoS Cache Poisoning Advisory for Bind9 USN-7836-1

ubuntu

October 22, 2025

Several security issues were fixed in Bind.

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)

Topics Covered

security advisory denial of service Ubuntu important cache poisoning bind9

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.