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Ubuntu 20.04: Bind Important Denial of Service Cache Poisoning USN-7836-2

ubuntu
Calendar Grey November 12, 2025
Dist Ubuntu Esm H88
Critical updates fixed several issues in Bind for Ubuntu 20.04, addressing remote attacks and potential system compromise.
Several security issues were fixed in Bind.

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)

Topics%20covered

Topics Covered

security advisory denial of service bind Ubuntu important cache poisoning

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

Severity
important
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-7836-2

Topics%20covered

Topics Covered

security advisory denial of service bind Ubuntu important cache poisoning

Package Information

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