CVE-2026-78227

NLnet Labs Unbound 1.22.0 up to and including 1.26.1, has a use-after-free vulnerability when compiled for DNS-over-QUIC support with '--with-libngtcp2'. Each DoQ stream owns an output buffer that holds the DNS response. ngtcp2's retransmission buffer keeps a shallow pointer into the output buffe...

CVE-2026-78227

NLnet Labs Unbound 1.22.0 up to and including 1.26.1, has a use-after-free vulnerability when compiled for DNS-over-QUIC support with '--with-libngtcp2'. Each DoQ stream owns an output buffer that holds the DNS response. ngtcp2's retransmission buffer keeps a shallow pointer into the output buffe...

SUSE-SU-2026:23360-1 Security update for unbound

This update for unbound fixes the following issues: Update to version 1.25.2. Security issues fixed: - CVE-2026-14586: DoS via assertion in libngtcp2 for DNS-over-QUIC environments with high concurrency bsc1271879. - CVE-2026-32665: Remote DNS-over-QUIC denial of service due to quic-size budget...

SUSE CVE-2026-14586

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, in DNS-over-QUIC environments, with high concurrency and under pressure, an assertion in libngtcp2 about monotonic timestamps could trigger and result in server termination and thus denial of service. When interfacing with libngtcp2, for...

Linux Distros Unpatched Vulnerability : CVE-2026-55991

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 1.22.0 up to and including 1.25.1, a remote unauthenticated client can trigger a libngtcp2 assertion if compiled with assertions on and...

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

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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...

AZL-92976 CVE-2026-55991 affecting package unbound for versions less than 1.25.2-1

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-2026-32665

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, when downstream DNS-over-QUIC DoQ is enabled, the first two bidirectional streams on a new QUIC connection streamid 0 and 4 bypass the per-stream 'quic-size' gate entirely, and large input buffers are allocated later, after only the 2-byte...

CVE-2026-41637

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, client terminated DNS-over-QUIC DoQ queries are not accounted properly by Unbound resulting in low-cost inflation of the waiting number of replies for already in-flight resolution queries. This results in degradation of resolution service f...

AZL-92985 CVE-2026-41637 affecting package unbound for versions less than 1.25.2-1

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, client terminated DNS-over-QUIC DoQ queries are not accounted properly by Unbound resulting in low-cost inflation of the waiting number of replies for already in-flight resolution queries. This results in degradation of resolution service f...

AZL-92952 CVE-2026-32665 affecting package unbound for versions less than 1.25.2-1

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, when downstream DNS-over-QUIC DoQ is enabled, the first two bidirectional streams on a new QUIC connection streamid 0 and 4 bypass the per-stream 'quic-size' gate entirely, and large input buffers are allocated later, after only the 2-byte...

AZL-92967 CVE-2026-14586 affecting package unbound for versions less than 1.25.2-1

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, in DNS-over-QUIC environments, with high concurrency and under pressure, an assertion in libngtcp2 about monotonic timestamps could trigger and result in server termination and thus denial of service. When interfacing with libngtcp2, for...

CVE-2026-14586

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, in DNS-over-QUIC environments, with high concurrency and under pressure, an assertion in libngtcp2 about monotonic timestamps could trigger and result in server termination and thus denial of service. When interfacing with libngtcp2, for...

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-2026-14586

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, in DNS-over-QUIC environments, with high concurrency and under pressure, an assertion in libngtcp2 about monotonic timestamps could trigger and result in server termination and thus denial of service. When interfacing with libngtcp2, for...

unbound: Unbound: Denial of Service via crafted DNS-over-QUIC connection

A flaw was found in Unbound. A remote, unauthenticated client can exploit this vulnerability by sending a specially crafted DNS-over-QUIC DoQ connection and a single DNS query. This can trigger an assertion failure in the libngtcp2 library, leading to the termination of the entire Unbound process...

unbound: Unbound: Denial of Service via assertion failure in DNS-over-QUIC environments

A flaw was found in Unbound. Under heavy DNS-over-QUIC DoQ traffic, a timing discrepancy in Unbound’s libngtcp2 library can trigger an assertion failure. This causes the server to crash unexpectedly, resulting in a denial of service DoS...

CVE-2026-55991

CVE-2026-55991 affects NLnet Labs Unbound 1.22.0–1.25.1. A remote unauthenticated DoQ client can trigger a libngtcp2 assertion by passing an erroneous error value when ngtcp2_conn_writev_stream() returns NGTCP2_ERR_STREAM_DATA_BLOCKED and Unbound calls ngtcp2_ccerr_set_application_error() with -1...

CVE-2026-41637 Degradation of resolution service from improperly accounted client-terminated DNS-over-QUIC queries

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, client terminated DNS-over-QUIC DoQ queries are not accounted properly by Unbound resulting in low-cost inflation of the waiting number of replies for already in-flight resolution queries. This results in degradation of resolution service f...