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-2026-50046

In NLnet Labs Unbound 1.15.0 up to and including 1.25.1, the TLS server name used for DNS-over-TLS DoT forwarded queries is tied to a struct's 'servicedquery' lifetime but also referenced by another struct 'waitingtcp'. When the owning struct is jostled out of the mesh while the DoT TCP stream is...

ALPINE-CVE-2026-50046

In NLnet Labs Unbound 1.15.0 up to and including 1.25.1, the TLS server name used for DNS-over-TLS DoT forwarded queries is tied to a struct's 'servicedquery' lifetime but also referenced by another struct 'waitingtcp'. When the owning struct is jostled out of the mesh while the DoT TCP stream is...

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-2026-32665

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...

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...

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-2026-50046

In NLnet Labs Unbound 1.15.0 up to and including 1.25.1, the TLS server name used for DNS-over-TLS DoT forwarded queries is tied to a struct's 'servicedquery' lifetime but also referenced by another struct 'waitingtcp'. When the owning struct is jostled out of the mesh while the DoT TCP stream is...

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...

unbound: Unbound: Denial of Service via improper validation of DNS-over-QUIC client length

A flaw was found in Unbound when DNS-over-QUIC DoQ is enabled. An attacker could exploit improper validation of client-provided data length, leading to excessive memory allocation. This can cause the system to exceed its configured memory limits for QUIC connections, resulting in a Denial of...

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 due to freed pointer dereference in DNS-over-TLS handling

A use-after-free flaw was found in Unbound's DNS-over-TLS DoT forwarded query handling. A remote attacker can exploit a timing error during TLS handshake failures on a server under load to trigger a daemon crash, resulting in a Denial of Service DoS...

unbound: Unbound: Denial of Service via terminated DNS-over-QUIC queries

A flaw was found in Unbound, a Domain Name System DNS resolver. A remote attacker can exploit this vulnerability by sending and immediately terminating DNS-over-QUIC DoQ queries. This improper handling of terminated queries can lead to a build-up of pending responses, causing a degradation of...

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-2026-55991

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...

EUVD-2026-47683

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-2026-50046 Possible heap use-after-free in an error path when a DoT forwarded query is jostled out

In NLnet Labs Unbound 1.15.0 up to and including 1.25.1, the TLS server name used for DNS-over-TLS DoT forwarded queries is tied to a struct's 'servicedquery' lifetime but also referenced by another struct 'waitingtcp'. When the owning struct is jostled out of the mesh while the DoT TCP stream is...

CVE-2026-50046 Possible heap use-after-free in an error path when a DoT forwarded query is jostled out

In NLnet Labs Unbound 1.15.0 up to and including 1.25.1, the TLS server name used for DNS-over-TLS DoT forwarded queries is tied to a struct's 'servicedquery' lifetime but also referenced by another struct 'waitingtcp'. When the owning struct is jostled out of the mesh while the DoT TCP stream is...

CVE-2026-50046

In NLnet Labs Unbound 1.15.0 up to and including 1.25.1, the TLS server name used for DNS-over-TLS DoT forwarded queries is tied to a struct's 'servicedquery' lifetime but also referenced by another struct 'waitingtcp'. When the owning struct is jostled out of the mesh while the DoT TCP stream is...