nlnetlabs vulnerabilities

Products

• unbound 61
• nsd 12
• routinator 12
• ldns 8
• name server daemon 2
• Net::DNS 2
• bcder 1
• krill 1

Latest nlnetlabs CVEs

Newest publication first · page 1 of 4

1. CVE-2026-85501 Retrap: Novel Vulnerabilities to launch Algorithmic Complexity Attacks on DNSSEC

   Published 2026-09-16

   High·CVSS 7.5 EPSS 0.48%

   Novel vulnerabilities to launch algorithmic complexity attacks on DNSSEC have been researched under the term 'ReTrap'. These result in degradation of service when malicious zones are used to serve the algorithmic complexity vulnerabilities. NLnet Labs Unbound up to and including...

2. CVE-2026-82720 Use-after-free in DoH stream cleanup code path

   Published 2026-09-16

   Medium·CVSS 5.9 EPSS 0.38%

   NLnet Labs Unbound 1.12.0 up to and including 1.26.0 has a use-after-free vulnerability when compiled for DNS-over-HTTPs support with '--with-libnghttp2'. During failure code paths (i.e., RPZ drop query, jostle due to heavy traffic), a dropped DoH stream brings down the whole DoH...

3. CVE-2026-82717 CNAME synthesis could lead to heap corruption

   Published 2026-09-16

   High·CVSS 8.4 EPSS 0.78%

   In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in that can progressively corrupt heap memory and under certain systems and compilation options could lead to remote code execution. The vulnerability starts when CNAME synthesis during an upstream respon...

4. CVE-2026-81642 Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY

   Published 2026-09-16

   Critical·CVSS 9.1 EPSS 0.96%

   In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in the DNSSEC validator that enables denial of service and possible remote code execution as a result of digesting DNSKEYs. A DNSKEY with an owner compression pointer to its own RDATA can overflow the dig...

5. CVE-2026-81634 Possible heap buffer overflow during DNSSEC canonicalization

   Published 2026-09-16

   High·CVSS 7.5 EPSS 0.48%

   In NLnet Labs Unbound up to and including 1.26.0, a 255 length query name with a large TCP response can lead to a heap buffer overflow during the RRSet canonicalisation routine. This is caused by missing to add the first owner name into the buffer length check. A malicious actor...

6. CVE-2026-80225 Possible degradation of service from continuous queries on the same TCP/DoT connection

   Published 2026-09-16

   High·CVSS 7.5 EPSS 0.48%

   In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT conne...

7. CVE-2026-78227 Use-after-free in DoQ stream output buffer on reset re-transmission

   Published 2026-09-16

   Medium·CVSS 6.5 EPSS 0.34%

   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...

8. CVE-2026-77955 Possible ZONEMD verification bypass window

   Published 2026-09-16

   Medium·CVSS 4.4 EPSS 0.17%

   In NLnet Labs Unbound 1.13.2 up to and including 1.26.1, a vulnerability in ZONEMD configured zones (zonemd-check: yes) which are located below (but not at) a trust anchor allow for an attack window where (tampered with) zone contents are served (or stored to disk) prior to the Z...

9. CVE-2026-77860 'serve-expired' can bypass Unbound 'wait-limit'

   Published 2026-09-16

   Low·CVSS 3.7 EPSS 0.30%

   In NLnetLabs Unbound 1.20.0 up to and including 1.26.0, a vulnerability on the 'serve-expired' code path can cause a double decrement on the 'wait-limit' counter per client IP essentially bypassing one of the counter measures that was introduced for DNSBomb (CVE-2024-33655). A ma...

10. CVE-2026-19538 Bypass of BLOCKED ACL items on proxy protocol port over TCP or TLS

    Published 2026-08-26

    High·CVSS 8.2 EPSS 0.44%

    The BLOCKED access control list items that are evaluated to deny access on the the proxy protocol port can be bypassed completely when connecting over TCP or TLS and sending the query twice on connection that is kept open.

11. CVE-2026-19401 Remote UDP DoS by sending multiple DNS Cookie options

    Published 2026-08-26

    High·CVSS 8.2 EPSS 0.46%

    Any remote client can crash a (debugging/non-release build type) NSD serve child by sending it a special crafted message with a specially tuned number of DNS Cookie options (17 when UDP payload size is 512). By continuously crashing the serve childs, the remote client can severel...

12. CVE-2026-18916 Remote TCP DoS by throttling the TCP receive window

    Published 2026-08-26

    Medium·CVSS 6.9 EPSS 0.46%

    Any remote client can crash a NSD serve child, by throttling the TCP receive window after a TCP query. By continuously crashing the serve childs, the remote client can denial all TCP service to this NSD instance.

13. CVE-2026-18664 Wrong interpretation of ACL ranges

    Published 2026-08-26

    High·CVSS 8.2 EPSS 0.44%

    When ranges are used for access control (i.e. of the form 1.2.3.4-1.2.3.25), because NSD wrongly compares the IP address with the range on little endian systems, IPs that were meant to be allowed may be denied, and, IPs that were meant to be denied access could be allowed. An IPv...

14. CVE-2026-56444 Degradation of resolution service when 'discard-timeout' and 'serve-expired-client-timeout' are combined in unusual configuration

    Published 2026-07-22

    Medium·CVSS 5.9 EPSS 0.37%

    In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout > discard-timeout > 0' (contrary to the suggested values), the discard-timeout branch during the serve expired logic drops an aged clien...

15. CVE-2026-56416 Possible heap buffer overflow when validator canonicalizes RDATA that contains domain name

    Published 2026-07-22

    Medium·CVSS 4.8 EPSS 0.12%

    In NLnet Labs Unbound up to and including version 1.25.1, when the validator builds the canonical RDATA form for an RRSIG-covered PX/RP/MINFO/SOA RRset, it computes the address of the second embedded domain name as 'datstart + dname_valid(datstart, ...)' and passes it straight to...

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

    Published 2026-07-22

    Medium·CVSS 5.9 EPSS 0.37%

    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 cau...

17. CVE-2026-55990 Packet of death for a DNSCrypt misconfigured Unbound

    Published 2026-07-22

    Medium·CVSS 5.9 EPSS 0.25%

    In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, when the 'dnscrypt:' clause lists more 'dnscrypt-provider-cert:' files than there are matching 'dnscrypt-secret-key:' files, Unbound fills only the matched prefix and leaves the tail slots at the '0xdb' fill that libsodium's...

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

    Published 2026-07-22

    High·CVSS 7.5 EPSS 0.28%

    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...

19. CVE-2026-55717 'serve-expired-client-timeout' and 'response-ip' CNAME redirect could lead to a crash

    Published 2026-07-22

    Medium·CVSS 5.9 EPSS 0.24%

    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: <net> redirect' /'response-ip-data: <net> CNAME <target>' rule (or the RPZ 'rpz-cname-override' equivalent), a remote client who controls any delegated domain c...

20. CVE-2026-55708 Privacy/configuration issue when adding local data in views through 'unbound-control'

    Published 2026-07-22

    Low·CVSS 3.1 EPSS 0.16%

    In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, the 'view_local_data' and 'view_local_datas' 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 creati...

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

    Published 2026-07-22

    Low·CVSS 3.7 EPSS 0.24%

    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 obt...

22. CVE-2026-52863 Memory corruption could lead to crash and denial of service

    Published 2026-07-22

    Medium·CVSS 5.9 EPSS 0.37%

    In NLnet Labs Unbound 1.25.0 up to and including 1.25.1, a fix that makes the 'respip' and 'dns64' modules work together, creates a shallow copy of the view name in effect that could lead to memory corruption if the owner of the original view name is jostled out when Unbound is u...

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

    Published 2026-07-22

    Medium·CVSS 5.7 EPSS 0.17%

    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 secr...

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

    Published 2026-07-22

    Medium·CVSS 5.3 EPSS 0.25%

    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 seemingl...

25. CVE-2026-50248 BOGUS configured primary hostname accepted for XFR in auth/rpz zones

    Published 2026-07-22

    Medium·CVSS 6.5 EPSS 0.13%

    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...

Sources: CVE.org, NVD, CISA KEV, FIRST EPSS, OSV and public exploit-reference metadata. Product matching comes from the published CVE records. A proof-of-concept means public code exists; it is not evidence of exploitation.