Linux Distros Unpatched Vulnerability : CVE-2026-56444

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout discard-timeout ...

CVE-2026-56444 Degradation of resolution service when 'discard-timeout' and 'serve-expired-client-timeout' are combined in unusual configuration

In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout discard-timeout 0' contrary to the suggested values, the discard-timeout branch during the serve expired logic drops an aged client reply without...

CVE-2026-56444

CVE-2026-56444 affects NLnet Labs Unbound 1.20.0 through 1.25.1. When configured with serve-expired: yes and serve-expired-client-timeout > discard-timeout > 0, the discard-timeout branch in the serve-expired logic fails to decrement the counter for aged client replies, unlike other branche...

CVE-2026-56444 Degradation of resolution service when 'discard-timeout' and 'serve-expired-client-timeout' are combined in unusual configuration

In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout discard-timeout 0' contrary to the suggested values, the discard-timeout branch during the serve expired logic drops an aged client reply without...

CVE-2026-56444

In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout discard-timeout 0' contrary to the suggested values, the discard-timeout branch during the serve expired logic drops an aged client reply without...

PT-2026-63393

Name of the Vulnerable Software and Affected Versions NLnet Labs Unbound versions 1.20.0 through 1.25.1 Description An issue exists when the software is configured with serve-expired: yes and serve-expired-client-timeout is greater than discard-timeout where discard-timeout is greater than 0. In...

unbound: Unbound: Denial of Service due to degraded resolution performance in jostle logic

A flaw was found in Unbound. An adversary who can query a vulnerable Unbound instance and control a slow or malicious domain name server can exploit a vulnerability in the jostle logic. This flaw allows retransmitted queries to renew the age of slow-running queries, preventing them from being...

CVE-2026-42534

A flaw was found in Unbound. An adversary who can query a vulnerable Unbound instance and control a slow or malicious domain name server can exploit a vulnerability in the jostle logic. This flaw allows retransmitted queries to renew the age of slow-running queries, preventing them from being...

SUSE CVE-2026-42534

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the jostle logic that could defeat its purpose and degrade resolution performance. Retransmits of the same query could renew the age of slow running queries and not allow the jostle logic to see them as aged and potentia...

Jostle logic bypass degrades resolution performance

...

CVE-2026-42534

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the jostle logic that can degrade DNS resolution performance and, under coordinated attack, lead to denial of service. An adversary controlling a slow or malicious DNS server can cause duplicate slow queries to skew agin...

PT-2026-42129

Name of the Vulnerable Software and Affected Versions NLnet Labs Unbound versions prior to 1.25.1 Description An issue exists in the jostle logic that can degrade resolution performance. When the num-queries-per-thread limit is reached, the jostle logic identifies slow-resolving queries for...