[USN-8037-1] DNSdist vulnerabilities

[noreply+usn-bot at canonical.com]

==========================================================================
Ubuntu Security Notice USN-8037-1
February 12, 2026

dnsdist vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 25.10
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS

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)

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

Package Information:
  https://launchpad.net/ubuntu/+source/dnsdist/1.9.10-1ubuntu0.1
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