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Ubuntu 22.04 LTS dnsdist Important DoS Issues Fixed USN-8037-1

ubuntu
Calendar Grey February 12, 2026
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Fixes for several security issues in dnsdist including memory management and denial of service vulnerabilities in Ubuntu.
Several security issues were fixed in dnsdist.

Summary

Several security issues were fixed in dnsdist.

Software Description:

- dnsdist: A highly DNS-, DoS- and abuse-aware loadbalancer

Details:

It was discovered that HTTP/2, which is used/vendored by DNSdist, did not

properly account for resources when handling client-triggered stream

resets. An attacker could possibly use this issue to cause a

denial of service. (CVE-2025-8671)

It was discovered that DNSdist did not properly manage memory limits when

handling an unlimited number of queries on a single TCP connection. An

attacker could possibly use this issue to cause a denial of service.

(CVE-2025-30193)

It was discovered that DNSdist, when configured with the nghttp2 library,

did not correctly process certain DNS over HTTPS queries. An attacker

could possibly use this cause a denial of service. (CVE-2025-30187)

Topics%20covered

Topics Covered

security advisory denial of service DoS Ubuntu important dnsdist

Update Instructions

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

Ubuntu 25.10
  dnsdist                         1.9.10-1ubuntu0.1

Ubuntu 24.04 LTS
  dnsdist                         1.8.3-2ubuntu0.1~esm1
                                  Available with Ubuntu Pro

Ubuntu 22.04 LTS
  dnsdist                         1.6.1-1ubuntu0.1~esm2
                                  Available with Ubuntu Pro

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

References

https://ubuntu.com/security/notices/USN-8037-1

CVE-2025-30187, CVE-2025-30193, CVE-2025-8671

Severity
important
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-8037-1

Topics%20covered

Topics Covered

security advisory denial of service DoS Ubuntu important dnsdist

Package Information

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