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Medium WID-SEC-2026-2492 24 CVEs

Unbound: Mehrere Schwachstellen

Published Jul 22, 2026 · Updated Nov 10, 2026 · Revision 24 · de

Vendor: amazon Vendor: Debian Vendor: Fedora Vendor: IBM Vendor: OpenBSD Vendor: Oracle Vendor: Red Hat Vendor: RESF Vendor: SUSE Vendor: Ubuntu Product: Enterprise Linux Product: Linux Product: Linux Product: Linux Product: Linux Product: Linux Product: Linux 2 Product: OpenBSD Product: openSUSE Product: QRadar SIEM Product: Rocky Linux Platform: Linux

Summary

Ein Angreifer kann mehrere Schwachstellen in Unbound ausnutzen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Daten zu manipulieren, und um Sicherheitsvorkehrungen zu umgehen.

Product

Unbound ist ein validierender, rekursiver DNS-Resolver.

Vulnerabilities 24

  • High 7.5
    CVE-2026-32665

    Remote DNS-over-QUIC denial of service due to `quic-size` budget bypass

    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 (stream_id 0 and 4) bypass the per-stream 'quic-size' gate entirely, and large input buffers …

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux
  • High 7.5
    CVE-2026-40691

    Packet of death for DNSCrypt over TCP

    In Unbound 1.9.0 up to and including 1.25.1, when a DNSCrypt query is received over TCP, the routine that encrypts the reply in place fails to bound the reply length against the destination buffer size. The size clamp that protects the UDP path is not applied…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux
  • High 7.5
    CVE-2026-44690

    Cross-zone wildcard cache poisoning via RRSIG.labels manipulation

    In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, insufficient validation of the RRSIG.Labels field combined with premature cache writes during RFC 8198 aggressive NSEC processing leads to cache poisoning that permits a malicious actor controlling a sin…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • High 7.5
    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 nam…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 6.5
    CVE-2026-50248

    BOGUS configured primary hostname accepted for XFR in auth/rpz zones

    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…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 6.3
    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 s…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 5.9
    CVE-2026-14586

    Assertion in libngtcp2 when under pressure in high concurrency DNS-over-QUIC environments

    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. W…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux
  • Medium 5.9
    CVE-2026-44621

    Libunbound applications configured with 'unwanted-reply-threshold' could eventually be abruptly terminated

    With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and libunbound needs to call 'libworker_alloc_cleanup…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 5.9
    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 ('serviced_query') lifetime but also referenced by another struct ('waiting_tcp'). When the owning struct is jostl…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 5.9
    CVE-2026-52863

    Memory corruption could lead to crash and denial of service

    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 …

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 5.9
    CVE-2026-55717

    'serve-expired-client-timeout' and 'response-ip' CNAME redirect could lead to a crash

    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 a…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 5.9
    CVE-2026-55990

    Packet of death for a DNSCrypt misconfigured Unbound

    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' …

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux
  • Medium 5.9
    CVE-2026-55991

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

    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 D…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux
  • Medium 5.9
    CVE-2026-56444

    Degradation of resolution service when 'discard-timeout' and 'serve-expired-client-timeout' are combined in unusual configuration

    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 logi…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 5.7
    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 …

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 5.3
    CVE-2026-50045

    'max-global-quota' reset by DNSSEC validation restarts

    In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, a single client query for a deeply nested name under a DNSSEC-signed parent can cause Unbound to send more upstream packets per client query than the configured 'max-global-quota'. This effectively bypa…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 5.3
    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 a…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Medium 4.8
    CVE-2026-56416

    Possible heap buffer overflow when validator canonicalizes RDATA that contains domain name

    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 …

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Low 3.7
    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 result…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux
  • Low 3.7
    CVE-2026-42955

    Extra fix for CVE-2026-40622 to also clamp the TTL of A/AAAA records disallowing a one-time 'ghost domain' delegation renewal via glue records

    In NLnet Labs Unbound 1.16.2 up to and including 1.25.1, a similar vulnerability as with CVE-2026-40622 in the 'ghost domain names' family of attacks was found in Unbound that could extend the ghost domain window by up to one cached TTL configured value for A…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Low 3.7
    CVE-2026-44687

    Off-by-one error in 'harden-below-nxdomain' logic can shadow a stub/forward zone by a legitimate parent's NXDOMAIN

    In NLnet Labs Unbound 1.13.2 up to and including 1.25.1, stub or forward zones where the name is below an intermediate labed below a DNSSEC signed zone could be shadowed by the intermediate label's secure NXDOMAIN answer from the parent. This is caused by an …

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Low 3.7
    CVE-2026-46582

    A wildcard replay, as another piece of data, triggers poisoning in the serve expired reply path

    In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, a replay of a wildcard rrset as another piece of data, could be briefly considered DNSSEC secure based only on the RRSIG validation and stored into cache, before later validation treats it as bogus based…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Low 3.7
    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. …

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine
  • Low 3.1
    CVE-2026-55708

    Privacy/configuration issue when adding local data in views through 'unbound-control'

    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…

    NLnet Labs Unbound unbound unbound Debian Ubuntu Azure Linux Alpine

Revision history

  1. #24

    Neue Updates von Ubuntu aufgenommen

  2. #23

    Neue Updates von Red Hat aufgenommen

  3. #22

    Neue Updates von IBM aufgenommen

  4. #21

    Neue Updates von SUSE aufgenommen

  5. #20

    Neue Updates von Ubuntu aufgenommen

  6. #19

    Neue Updates von SUSE aufgenommen

  7. #18

    Neue Updates von openSUSE aufgenommen

  8. #17

    Neue Updates von SUSE aufgenommen

  9. #16

    Neue Updates von SUSE aufgenommen

  10. #15

    Neue Updates aufgenommen

  11. #14

    Neue Updates von Oracle Linux aufgenommen

  12. #13

    Neue Updates von Rocky Enterprise Software Foundation aufgenommen

  13. #12

    Neue Updates von Red Hat und Debian aufgenommen

  14. #11

    Neue Updates von Rocky Enterprise Software Foundation aufgenommen

  15. #10

    Neue Updates von Rocky Enterprise Software Foundation, Oracle Linux und Red Hat aufgenommen

  16. #9

    Neue Updates von SUSE aufgenommen

  17. #8

    Neue Updates von Red Hat aufgenommen

  18. #7

    Neue Updates von SUSE aufgenommen

  19. #6

    Neue Updates von Rocky Enterprise Software Foundation aufgenommen

  20. #5

    Neue Updates von Red Hat und Rocky Enterprise Software Foundation aufgenommen

  21. #4

    Neue Updates von SUSE aufgenommen

  22. #3

    Neue Updates von Amazon aufgenommen

  23. #2

    Neue Updates von Fedora aufgenommen

  24. #1

    Initiale Fassung

References