Linux Distros Unpatched Vulnerability : CVE-2026-50243

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 1.6.2 up to and including 1.25.1, when Unbound is configured with the 'respip' module in front of the validator together with a...

CVE-2026-40691

A flaw was found in Unbound, a domain name system DNS resolver. When Unbound is configured with DNSCrypt support, a remote attacker could send a specially crafted DNSCrypt query over TCP. This malicious query could cause a memory error, leading to a server crash and a Denial of Service DoS. This...

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-2026-50248

In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, when an auth/rpz zone has a configured primary hostname that resolves to BOGUS A/AAAA, it is still considered as a possible XFR endpoint. A malicious actor that can spoof the hostname's A/AAAA record no valid RRSIG required becomes the zone'...

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-2026-14586

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: Cache poisoning via insufficient RRSIG.Labels validation and premature cache writes

A flaw was found in Unbound. Insufficient validation of the RRSIG.Labels field, combined with premature cache writes during RFC 8198 aggressive NSEC processing, can lead to cache poisoning. This vulnerability allows a malicious actor, controlling a single delegated zone, to poison arbitrary sibli...

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-2026-47680

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-2026-54478 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-2026-50252

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-2026-50252 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-2026-50248

In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, when an auth/rpz zone has a configured primary hostname that resolves to BOGUS A/AAAA, it is still considered as a possible XFR endpoint. A malicious actor that can spoof the hostname's A/AAAA record no valid RRSIG required becomes the zone'...

CVE-2026-50243 'response-ip'/'rpz' can rewrite BOGUS answers instead of returning SERVFAIL

In NLnet Labs Unbound 1.6.2 up to and including 1.25.1, when Unbound is configured with the 'respip' module in front of the validator together with a 'response-ip' redirect rule or an RPZ file with an RPZ-IP trigger, the rewriting handler does not check the security status of the upstream answer...

CVE-2026-50243

In NLnet Labs Unbound 1.6.2 up to and including 1.25.1, when Unbound is configured with the 'respip' module in front of the validator together with a 'response-ip' redirect rule or an RPZ file with an RPZ-IP trigger, the rewriting handler does not check the security status of the upstream answer...

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-2026-44690

The CVE-2026-44690 entry concerns NLnet Labs Unbound versions 1.7.0 through 1.25.1 where insufficient validation of the RRSIG.Labels field combined with premature cache writes during RFC 8198 aggressive NSEC processing enables cache poisoning. A malicious actor controlling a single delegated zone...

PT-2026-63377

Name of the Vulnerable Software and Affected Versions NLnet Labs Unbound versions 1.7.0 through 1.25.1 Description Insufficient validation of the RRSIG.Labels field and premature cache writes during RFC 8198 aggressive NSEC processing enable cache poisoning. An attacker controlling a single...

RHEL 8 : unbound (RHSA-2026:24365)

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:24365 advisory. The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver. Security Fixes: unbound: Heap overflow and crash...