We believe that the bug you reported is fixed in the latest version of
unbound, which is due to be installed in the Debian FTP archive.
A summary of the changes between this version and the previous one is
attached.
Thank you for reporting the bug, which will now be closed. If you
have further comments please address them to 1142539@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.
Debian distribution maintenance software
pp.
Michael Tokarev <mjt@tls.msk.ru> (supplier of updated unbound package)
(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Thu, 17 Sep 2026 11:55:59 +0300
Source: unbound
Architecture: source
Version: 1.26.1-0+deb13u1
Distribution: trixie-security
Urgency: medium
Maintainer: unbound packagers <unbound@packages.debian.org>
Changed-By: Michael Tokarev <mjt@tls.msk.ru>
Closes: 1096189 1142539
Changes:
unbound (1.26.1-0+deb13u1) trixie-security; urgency=medium
.
* New upstream release fixing numerous security and other issues and contains
some enhancements.
.
Traditionally in Debian, bugs in stable versions are fixed by providing
a back-port of a fix from later upstream version to the version in Debian
stable. With unbound, fixes in subsequent versions can not be applied
directly to the version in Debian stable, as there were multiple other code
changes in these areas. Many of these changes fixes other issues (security
or not). Some changes are in areas with complex logic, hence requires
creat care when back-porting to older releases. And the result of such
back-porting becomes unique and rather unpredictable. So instead of trying
to provide fixes for older version in Debian stable, we decided to provide
current upstream version of unbound, - the same as currently available in
Debian Sid. The packaging is made very similar too.
.
Recent security fixes:
.
o CVE-2026-81642 - severity: CRITICAL
Heap buffer overflow and possible Remote Code Execution
when digesting DNSKEY
o CVE-2026-81634 - severity: HIGH
Possible heap buffer overflow during DNSSEC canonicalization
o CVE-2026-82717 - severity: HIGH
CNAME synthesis could lead to heap corruption
o CVE-2026-77955 - severity: MEDIUM
Possible ZONEMD verification bypass window
o CVE-2026-78227 - severity: MEDIUM
Use-after-free in DoQ stream output buffer on reset re-transmission
o CVE-2026-80225 - severity: MEDIUM
Possible degradation of service from continuous queries
on the same TCP/DoT connection
o CVE-2026-82720 - severity: MEDIUM
Use-after-free in DoH stream cleanup code path
o CVE-2026-85501 - severity: MEDIUM
Retrap: Novel Vulnerabilities to launch Algorithmic Complexity Attacks
on DNSSEC
o CVE-2026-77860 - severity: LOW
'serve-expired' can bypass Unbound 'wait-limit'
o CVE-2026-32665 - severity: HIGH
Remote DNS-over-QUIC denial of service due to `quic-size` budget bypass
o CVE-2026-40691 - severity: HIGH
Packet of death for DNSCrypt over TCP
o CVE-2026-44690 - severity: HIGH
Cross-zone wildcard cache poisoning via RRSIG.labels manipulation
o CVE-2026-55973 - severity: HIGH
'dns-error-reporting: yes' leads to stack buffer overflow
o CVE-2026-14586 - severity: MEDIUM
Assertion in libngtcp2 when under pressure in high concurrency
DNS-over-QUIC environments
o CVE-2026-44621 - severity: MEDIUM
Libunbound applications configured with 'unwanted-reply-threshold'
could eventually be abruptly terminated
o CVE-2026-50045 - severity: MEDIUM
'max-global-quota' reset by DNSSEC validation restarts
o CVE-2026-50046 - severity: MEDIUM
Possible heap use-after-free in an error path when
a DoT forwarded query is jostled out
o CVE-2026-50243 - severity: MEDIUM
response-ip/rpz can rewrite BOGUS answers instead of returning SERVFAIL
o CVE-2026-50248 - severity: MEDIUM
BOGUS configured primary hostname accepted for XFR in auth/rpz zones
o CVE-2026-50251 - severity: MEDIUM
Attacker supplied 0.0.0.0/:: glue triggers defensive full-cache flush
o CVE-2026-50252 - severity: MEDIUM
Possible cache poisoning attack by mapping source port population
per thread
o CVE-2026-52863 - severity: MEDIUM
Memory corruption could lead to crash and denial of service
o CVE-2026-55717 - severity: MEDIUM
'serve-expired-client-timeout' and 'response-ip' CNAME redirect
could lead to a crash
o CVE-2026-55990 - severity: MEDIUM
Packet of death for a DNSCrypt misconfigured Unbound
o CVE-2026-55991 - severity: MEDIUM
Remote DNS-over-QUIC (DoQ) flow-control assertion failure in libngtcp2
o CVE-2026-56416 - severity: MEDIUM
Possible heap buffer overflow when validator canonicalizes RDATA
that contains domain name
o CVE-2026-56444 - severity: MEDIUM
Degradation of resolution service when 'discard-timeout' and
'serve-expired-client-timeout' are combined in unusual configuration
o CVE-2026-41637 - severity: LOW
Degradation of resolution service from improperly accounted
client-terminated DNS-over-QUIC queries
o CVE-2026-42955 - severity: LOW
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
o CVE-2026-44687 - severity: LOW
Off-by-one error in 'harden-below-nxdomain' logic can shadow
a stub/forward zone by a legitimate parent's NXDOMAIN
o CVE-2026-46582 - severity: LOW
A wildcard replay, as another piece of data, triggers poisoning
in the serve expired reply path
o CVE-2026-54478 - severity: LOW
DNS Cookie bypass when combined with proxy-protocol use
o CVE-2026-55708 - severity: LOW
Privacy/configuration issue when adding local data in views
through 'unbound-control'
.
Other notable user-visible changes and fixes. For complete list, please
see /usr/share/doc/unbound/changelog.gz
.
o ICANN Bundle Update: Refreshed icannbundle.pem certificates in
unbound-anchor to include public keys valid for 2009–2029 and 2025–2045
o Transfer Limits: Added max-transfer-size and max-transfer-time directives
to limit authorization zone (auth-zone) and RPZ transfer sizes and times
to harden against unbounded transfers.
o New Zone Types: Introduced block_aaaa static zone type to suppress AAAA
queries, plus block_a_wdata and block_aaaa_wdata to support custom local
data fallback.
o Management Improvements: Overloaded local_data_remove
to allow the removal of precise records.
o Fix for the Jiggle Attack. The server is fixed to answer with errors
for error cases, and does not stay silent. In addition, the error
replies do not contain parts of the incoming query. This is more
conformant, stops reflection and stops it as a covert channel.
o Fix EDNS extended RCODE reflection. This fixes that the server does not
echo extended rcode values after class chaos queries.
o Fix for iterator RCODE handling of YXDOMAIN. This fixes that the server
only accepts YXDOMAIN answers that contain a DNAME record. This stops
bad answers, and checks that the authoritative server gives correct
replies.
o Fix for missing bounds check for decompressing dnames for downloaded
authority zones. This fixes that the server could end up with malformed
zone content after receiving truncated packet contents from an AXFR.
In addition, the domain names in the SOA rdata are checked before the
authority code picks up the zone serial.
o Fix that upstream TLS connections are not reused as TLS connections for
a different name, at the same IP. This checks that the tls name is
correct when reusing the upstream connections.
o Fix that signatures are not allowed with revoked dnskeys.
o Fix that a DNAME with an unsigned CNAME is checked for the correct match.
This stops that for certain zone configurations an unchecked unsigned
CNAME could get secure status.
o Fix handling of wildcard CNAMEs in the chain of trust. An improper
wildcard in the chain of trust would send the retries to the wrong
upstream. Also it could label the step in the chain of trust as secure,
when it was not.
o Introduce new 'tls-protocols' configuration option that specifies which
of the supported TLS protocols will be used.
o Fix RFC7766 compliance when client sends EOF over TCP.
It stops pending replies and closes.
o Fix to shorten RRSIG count in scrubber, this protects against an overly
large number of RRSIGs. It can be configured with `iter-scrub-rrsig: 8`,
it has default 8.
o Fix for EDNS client subnet so that it does not store SERVFAIL in the
global cache after a failed lookup, such as timeouts. A failure entry is
stored in the subnet cache, for the query name, for a couple of seconds.
Queries can continue to use the subnet cache during that time.
o Fix to allow the control-interface config to use ip@port notation.
o Fix to check for invalid http content length and chunk size, and to check
the RR rdata field lengths when decompressing and inserting RRs from
an authority zone transfer. This stops large memory use and heap
buffer-overflow read errors.
o Fix to ignore out-of-zone DNAME records for CNAME synthesis.
Fix so that a reload checks if the files have changed, and if so, reload
the contexts. Also for DoH, DoQ and outgoing DoT.
o Apply cache TTL policy to DNAME and synthesized CNAME on wire path.
o Fix for DNS Rebinding Bypass via SVCB/HTTPS Records in Unbound.
o Allow synthesized DNAME TTL=0 to be served from cache within grace
period. The responses are served from cache within a 1-second grace
period. Reduces recursion when authoritative servers return DNAME with
TTL=0 (RFC 2308). Response still returns TTL=0 to clients.
o On Linux systems log the system-wide unique thread ID instead of
Unbound's internal thread counter.
o Introduce the 'log-thread-id' configuration option to manage logging the
system-wide Linux thread ID for easier debugging with system tools.
o Mesh reply counters. This adds statistics num.queries.replyaddr_limit
and requestlist.current.replies.
o Add extra statistic to track the number of signature validation
operations. Adds 'num.valops' to extended statistics.
o Fix for cname chain length with qtype ANY and qname minimisation.
o Change default for so-sndbuf to 4m, to mitigate a cross-layer issue where
the UDP socket send buffers are exhausted waiting for ARP/NDP resolution.
o Increase default to `num-queries-per-thread: 2048`, when unbound is
compiled with libevent. It makes saturation of the task queue more
resource intensive and less practical.
o DNS Error Reporting (RFC 9567). Introduces new configuration option
'dns-error-reporting' and new statistics for 'num.dns_error_reports'.
o Redis read-only replica support. Introduces new 'redis-replica-*'
options for the Redis cache backend.
o Exempt loopback addresses from wait-limit.
o Fix wait-limit-netblock and wait-limit-cookie-netblock config parse
to allow two arguments.
o Fast Reload. The unbound-control fast_reload is added. It reads
changed config in a thread, then only briefly pauses the service threads,
that keep running. DNS service is only interrupted briefly.
o Make the default value of module-config "validator iterator" regardless
of compilation options. --enable-subnet would implicitly change the
value to enable the subnetcache module by default in the past.
o Add unbound members group access to control key.
o Add resolver.arpa and service.arpa to the default locally served zones.
o Use TCP_NODELAY on TLS sockets to speed up the TLS handshake.
o Serve expired cache update fixes. Fixes a regression bug with
serve-expired that appeared in 1.22.0 and would not allow the iterator
to update the cache with not-yet-validated entries resulting in increased
outgoing traffic. Closes: #1142539
o The default value of serve-expired-ttl is set to 86400 (1 day)
as suggested by RFC8767.
o Increase the default of max-global-quota to 200 from 128 after
operational feedback. Still keeping the possible amplification factor
(CAMP related issues) in the hundreds.
o Fix for the serve expired DNSSEC information fix, it would not allow
current delegation information be updated in cache. The fix allows
current delegation and validation recursion information to be updated,
but as a consequence no longer has certain expired information around
for later dnssec valid expired responses.
o Statistics for discard-timeout and wait-limit.
.
* Other packaging changes:
- d/rules,d/libunbound-dev.install: drop static library and deps
(Closes: #1096189)
- unbound-helper: do not update resolvconf if it is systemd-resolved
- d/unbound.service: set empty DAEMON_OPTS= to avoid warning from systemd
- d/upstream/signing-key.asc: update with the new upstream key
- d/unbound.conf.d/remote-control.conf: fix typo
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