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

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

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-2026-55973 'dns-error-reporting: yes' leads to stack buffer overflow

In NLnet Labs Unbound 1.23.0 up to and including 1.25.1, when 'dns-error-reporting: yes' is set, the EDNS Report-Channel option code 18 from the last upstream response is read and uses the option's length as the length of the agent domain. When a domain name check is performed on the agent domain...

CVE-2026-55973 'dns-error-reporting: yes' leads to stack buffer overflow

In NLnet Labs Unbound 1.23.0 up to and including 1.25.1, when 'dns-error-reporting: yes' is set, the EDNS Report-Channel option code 18 from the last upstream response is read and uses the option's length as the length of the agent domain. When a domain name check is performed on the agent domain...

CVE-2026-55973

CVE-2026-55973 affects NLnet Labs Unbound 1.23.0 through 1.25.1. When dns-error-reporting: yes is enabled, the EDNS Report-Channel option (code 18) length from the last upstream response is treated as the length of the agent domain. If the agent domain contains garbage after the domain, those byt...

EUVD-2026-47680

In NLnet Labs Unbound 1.10.0 up to and including 1.25.1, when 'serve-expired: yes' is set together with a 'response-ip: redirect' /'response-ip-data: CNAME ' rule or the RPZ 'rpz-cname-override' equivalent, a remote client who controls any delegated domain can crash the daemon. The...

CVE-2026-55708

In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, the 'viewlocaldata' and 'viewlocaldatas' commands of 'unbound-control' create a bare local zones tree for an already configured named view when the view is configured with no local data to begin with. However, the creation through the contro...

EUVD-2026-47679

In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, the 'viewlocaldata' and 'viewlocaldatas' commands of 'unbound-control' create a bare local zones tree for an already configured named view when the view is configured with no local data to begin with. However, the creation through the contro...

CVE-2026-54478 DNS Cookie bypass when combined with proxy-protocol use

In NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXYv2-declared client. One server cookie obtained through a...

CVE-2026-54478 DNS Cookie bypass when combined with proxy-protocol use

In NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXYv2-declared client. One server cookie obtained through a...

EUVD-2026-47678

In NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXYv2-declared client. One server cookie obtained through a...

CVE-2026-54478

In NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXYv2-declared client. One server cookie obtained through a...

CVE-2026-50252 Possible cache poisoning attack by mapping source port population per thread

In NLnet Labs Unbound 1.4.22 up to and including 1.25.1, UDP source port is randomized and intended to serve as a secret value that increases the entropy of DNS transactions. When resolver load balancing policies depend on the source port while their outcome is revealed this secrecy is undermined...

CVE-2026-50252

In NLnet Labs Unbound 1.4.22 up to and including 1.25.1, UDP source port is randomized and intended to serve as a secret value that increases the entropy of DNS transactions. When resolver load balancing policies depend on the source port while their outcome is revealed this secrecy is undermined...

EUVD-2026-47676

In NLnet Labs Unbound 1.4.22 up to and including 1.25.1, UDP source port is randomized and intended to serve as a secret value that increases the entropy of DNS transactions. When resolver load balancing policies depend on the source port while their outcome is revealed this secrecy is undermined...

CVE-2026-50252

In NLnet Labs Unbound 1.4.22 up to and including 1.25.1, the UDP source port is used as a secrecy element to increase DNS transaction entropy. When SO_REUSEPORT is enabled (default) and load balancing depends on the source port and IP address, this secrecy can be undermined. On startup Unbound pa...

CVE-2026-50252

In NLnet Labs Unbound 1.4.22 up to and including 1.25.1, UDP source port is randomized and intended to serve as a secret value that increases the entropy of DNS transactions. When resolver load balancing policies depend on the source port while their outcome is revealed this secrecy is undermined...

CVE-2026-50252

In NLnet Labs Unbound 1.4.22 up to and including 1.25.1, UDP source port is randomized and intended to serve as a secret value that increases the entropy of DNS transactions. When resolver load balancing policies depend on the source port while their outcome is revealed this secrecy is undermined...

CVE-2026-50251 Attacker supplied '0.0.0.0'/'::' glue triggers defensive full-cache flush

In NLnet Labs Unbound up to and including version 1.25.1, when 'unwanted-reply-threshold' is enabled set to any value greater than zero, glue records of 0.0.0.0/::0 can short-circuit Unbound, on systems that can direct such traffic, by issuing DNS queries and receiving seemingly unwanted replies...