CVE-2026-55991

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, a remote unauthenticated client can trigger a libngtcp2 assertion if compiled with assertions on and terminate the entire Unbound process using a single DNS-over-QUIC DoQ connection and one normal DNS query. This is caused by an erroneous...

CVE-2026-55991 Remote DNS-over-QUIC (DoQ) flow-control assertion failure in libngtcp2

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, a remote unauthenticated client can trigger a libngtcp2 assertion if compiled with assertions on and terminate the entire Unbound process using a single DNS-over-QUIC DoQ connection and one normal DNS query. This is caused by an erroneous...

CVE-2026-55717

Vulnerability CVE-2026-55717 affects NLnet Labs Unbound 1.10.0 through 1.25.1. When serve-expired is yes and a response-ip/ RPZ CNAME-based redirect is configured, a remote attacker controlling any delegated zone can crash the daemon. The serve-expired-client-timeout routine chase loop on the res...

EulerOS 2.0 SP10 : unbound (EulerOS-SA-2026-2717)

According to the versions of the unbound packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities : NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash give...

CVE-2026-42959

NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong counter to calculate write offsets fo...