Unbound 1.25.2

Unbound 1.25.2

This release has a number of security fixes.

The release is signed with the OpenPGP software signing key that is
in use since Jan 1st 2026:

User ID: NLnet Labs releases signing key G2 <releases@nlnetlabs.nl>
Key ID: A144 323D EAAC DF45
Fingerprint: 2310 1869 0C4D 903E F419  146A A144 323D EAAC DF45

The key is available from https://nlnetlabs.nl/signing-keys .

This release consolidates security fixes for issues reported over
a period of time. There are fixes for CVE-2026-14586, CVE-2026-32665,
CVE-2026-40691, CVE-2026-41637, CVE-2026-42955, CVE-2026-44621,
CVE-2026-44687, CVE-2026-44690, CVE-2026-46582, CVE-2026-50045,
CVE-2026-50046, CVE-2026-50243, CVE-2026-50248, CVE-2026-50251,
CVE-2026-50252, CVE-2026-52863, CVE-2026-54478, CVE-2026-55708,
CVE-2026-55717, CVE-2026-55973, CVE-2026-55990, CVE-2026-55991,
CVE-2026-56416 and CVE-2026-56444.

Bug Fixes

• Fix CVE-2026-14586, Assertion in libngtcp2 when under pressure
  in high concurrency DNS-over-QUIC environments. Thanks to Kunta
  Chu, Kaihua Wang, and Jianjun Chen from Tsinghua University,
  for the report.
• Fix CVE-2026-32665, Remote DNS-over-QUIC denial of
  service due to quic-size budget bypass. Thanks to N0zoM1z0
  (https://github.com/N0zoM1z0) for the report. In addition, thanks to
  Kunta Chu, Kaihua Wang, and Jianjun Chen from Tsinghua University,
  for also reporting this issue. In addition, thanks to Qifan Zhang,
  Palo Alto Networks, for also reporting this issue. In addition,
  thanks to Xuanchao Xie, for also reporting this issue.
• Fix CVE-2026-40691, Packet of death for DNSCrypt over TCP. Thanks
  to Qifan Zhang, Palo Alto Networks, for the report. In addition,
  thanks to Trung Nguyen (@everping) of CyStack, for also reporting
  this issue.
• Fix CVE-2026-41637, Degradation of resolution service from
  improperly accounted client-terminated DNS-over-QUIC queries. Thanks
  to Qifan Zhang, Palo Alto Networks, for the report.
• Fix 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. Thanks to Qifan Zhang, Palo
  Alto Networks, for the report.
• Fix CVE-2026-44621, Libunbound applications configured with
  'unwanted-reply-threshold' could eventually be abruptly
  terminated. Thanks to Qifan Zhang, Palo Alto Networks, for the
  report.
• Fix CVE-2026-44687, Off-by-one error in 'harden-below-nxdomain'
  logic can shadow a stub/forward zone by a legitimate parent's
  NXDOMAIN. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
• Fix CVE-2026-44690, Cross-zone wildcard cache poisoning via
  RRSIG.labels manipulation. Thanks to Qifan Zhang, Palo Alto
  Networks, for the report.
• Fix CVE-2026-46582, A wildcard replay, as another piece of data,
  triggers poisoning in the serve expired reply path. Thanks to
  Qifan Zhang, Palo Alto Networks, for the report.
• Fix CVE-2026-50045, 'max-global-quota' reset by DNSSEC validation
  restarts. Thanks to Kunjie Shang, University of Science and
  Technology of China, for the report.
• Fix CVE-2026-50046, Possible heap use-after-free in an error path
  when a DoT forwarded query is jostled out. Thanks to Qifan Zhang,
  Palo Alto Networks, for the report.
• Fix CVE-2026-50243, 'response-ip'/'rpz' can rewrite BOGUS answers
  instead of returning SERVFAIL. Thanks to Qifan Zhang, Palo Alto
  Networks, for the report.
• Fix CVE-2026-50248, BOGUS configured primary hostname accepted for
  XFR in auth/rpz zones. Thanks to Qifan Zhang, Palo Alto Networks,
  for the report.
• Fix CVE-2026-50251, Attacker supplied 0.0.0.0/:: glue triggers
  defensive full-cache flush. Thanks to Qifan Zhang, Palo Alto
  Networks, for the report.
• Fix CVE-2026-50252, Possible cache poisoning attack by mapping
  source port population per thread. Thanks to Inbal Schussheim and
  Amit Klein, Hebrew University, for the report.
• Fix CVE-2026-52863, Memory corruption could lead to crash and
  denial of service. Thanks to Qifan Zhang, Palo Alto Networks,
  for the report.
• Fix CVE-2026-54478, DNS Cookie bypass when combined with
  proxy-protocol use. Thanks to Qifan Zhang, Palo Alto Networks,
  for the report.
• Fix CVE-2026-55708, Privacy/configuration issue when adding local
  data in views through 'unbound-control'. Thanks to Qifan Zhang,
  Palo Alto Networks, for the report.
• Fix CVE-2026-55717, 'serve-expired-client-timeout' and 'response-ip'
  CNAME redirect could lead to a crash. Thanks to Qifan Zhang, Palo
  Alto Networks, for the report. In addition, thanks to Xin Wang,
  Jiapeng Li, and Jiajia Liu, Northwestern Polytechnical University,
  for also reporting this issue.
• Fix CVE-2026-55973, 'dns-error-reporting: yes' leads to stack buffer
  overflow. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
• Fix CVE-2026-55990, Packet of death for a DNSCrypt misconfigured
  Unbound. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
• Fix CVE-2026-55991, Remote DNS-over-QUIC (DoQ) flow-control
  assertion failure in libngtcp2. Thanks to Qifan Zhang, Palo Alto
  Networks, for the report. In addition, thanks to Xuanchao Xie,
  for also reporting this issue.
• Fix CVE-2026-56416, Possible heap buffer overflow when validator
  canonicalizes RDATA that contains domain name. Thanks to Qifan
  Zhang, Palo Alto Networks, for the report.
• Fix CVE-2026-56444, Degradation of resolution service when
  'discard-timeout' and 'serve-expired-client-timeout' are combined in
  unusual configuration. Thanks to Qifan Zhang, Palo Alto Networks,
  for the report. In addition, thanks to Xin Wang, Jiapeng Li,
  and Jiajia Liu, Northwestern Polytechnical University, for also
  reporting this issue. In addition, thanks to Haruki Oyama (Waseda
  University), for also reporting this issue.