========================================================================== Ubuntu Security Notice USN-7836-2 November 12, 2025
bind9 vulnerabilities
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 20.04 LTS
Summary:
Several security issues were fixed in Bind.
Software Description:
- bind9: Internet Domain Name Server
Details:
USN-7836-1 fixed vulnerabilities in Bind. This update provides the
corresponding fixes for Ubuntu 20.04 LTS.
Original advisory 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 20.04 LTS
bind9 1:9.18.30-0ubuntu0.20.04.2+esm1
Available with Ubuntu Pro
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-7836-2
https://ubuntu.com/security/notices/USN-7836-1
CVE-2025-40778, CVE-2025-40780, CVE-2025-8677
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