Security Fixes
~~~~~~~~~~~~~~
-- Fix outgoing zone transfers' quota issue.
-
- Unauthorized clients could consume outgoing zone transfers quota and
- block authorized zone transfer clients. This has been fixed.
- :gl:`#3589`
+- Limit resolver server list size. :cve:`2026-3592`
-- [CVE-2026-3592] Limit resolver server list size.
-
- When resolving a domain with many nameservers that share overlapping
+ When resolving a domain with many nameservers that shared overlapping
IP addresses (e.g., 10 NS records all pointing at the same set of
addresses), BIND could previously waste time querying duplicate
- addresses and build up excessively large server lists. Deduplicate
- addresses in the resolver's server list so that each unique IP is only
+ addresses and build up excessively large server lists. Addresses in
+ the resolver's server list are now deduplicated so that each unique IP is only
queried once per resolution attempt, regardless of how many NS records
- point to it and cap the number of addresses stored per nameserver name
- to 6 (combined A and AAAA), preventing memory and CPU overhead from
- domains with unusually large NS/glue sets. :gl:`#5641`
+ point to it. The number of addresses stored per nameserver name
+ is also now capped at six (combined A and AAAA), preventing memory and CPU overhead from
+ domains with unusually large NS/glue sets.
+
+ ISC would like to thank Shuhan Zhang from Tsinghua University for
+ reporting this issue. :gl:`#5641`
-- [CVE-2026-3039] Fix GSS-API resource leak.
+- Fix GSS-API resource leak. :cve:`2026-3039`
- Fixed a memory leak where each GSS-API TKEY negotiation leaked a
+ A memory leak was fixed where each GSS-API TKEY negotiation leaked a
security context inside the GSS library. An unauthenticated attacker
could exhaust server memory by sending repeated TKEY queries to a
- server with tkey-gssapi-keytab configured. The leaked memory was
+ server with :any:`tkey-gssapi-keytab` configured. The leaked memory was
allocated by the GSS library, bypassing BIND's memory accounting.
Multi-round GSS-API negotiation (GSS_S_CONTINUE_NEEDED) is now
rejected, as BIND never supported it correctly and Kerberos/SPNEGO
- completes in a single round. :gl:`#5752`
+ completes in a single round.
-- [CVE-2026-5946] Disable recursion, UPDATE, and NOTIFY for non-IN
- views.
+ ISC would like to thank Vitaly Simonovich for bringing this
+ vulnerability to our attention. :gl:`#5752`
+
+- Disable recursion, UPDATE, and NOTIFY for non-IN views.
+ :cve:`2026-5946`
Recursion, dynamic updates (UPDATE), and zone change notifications
(NOTIFY) are now disabled for views with a class other than IN (such
as CHAOS or HESIOD); authoritative service for non-IN zones (e.g.
version.bind in class CHAOS) continues to work as before. Servers
- configured with recursion yes in a non-IN view will log a warning at
- startup, and named-checkconf flags the same condition. UPDATE and
+ configured with :namedconf:ref:`recursion yes; <recursion>`
+ in a non-IN view log a warning at
+ startup, and :iscman:`named-checkconf` flags the same condition. UPDATE and
NOTIFY messages that specify the meta-classes ANY or NONE in the
question section are now rejected with FORMERR.
identified as CVE-2026-5946. ISC would like to thank Mcsky23 for
bringing these issues to our attention. :gl:`#5784`
-- [CVE-2026-5950] Avoid unbounded recursion loop.
+- Avoid unbounded recursion loop. :cve:`2026-5950`
A bug during bad server handling could cause the resolver to enter an
infinite loop, continuously sending queries to an upstream server with
ISC would like to thank Billy Baraja (BielraX) for bringing this issue
to our attention. :gl:`#5804`
-- [CVE-2026-5947] Fix crash in resolver when SIG(0)-signed responses are
- received under load.
+- Fix crash in resolver when SIG(0)-signed responses are received under
+ load. :cve:`2026-5947`
A resolver could crash when handling a SIG(0)-signed response if the
matching client query was cancelled while signature verification was
still in progress — for example, when the recursive-clients quota was
- exhausted. This has been fixed. :gl:`#5819`
-
-- Fix race condition in getsigningtime()
+ exhausted. This has been fixed.
- Compute qpzone_get_lock(elem->node) into a local variable while the
- heap lock is still held, rather than dereferencing the stale elem
- pointer after releasing the lock. A concurrent thread running
- setsigningtime() (e.g. via IXFR apply on a worker thread) could free
- the top-of-heap element between the heap lock release and the
- dereference, causing a use-after-free. :gl:`#5883`
+ ISC would like to thank Naoki Wakamatsu for bringing this
+ vulnerability to our attention. :gl:`#5819`
-- [CVE-2026-3593] Fix use-after-free in DNS-over-HTTPS when processing
- HTTP/2 SETTINGS frames.
+- Fix use-after-free error in DNS-over-HTTPS when processing HTTP/2
+ SETTINGS frames. :cve:`2026-3593`
- A use-after-free vulnerability in the DNS-over-HTTPS implementation
- could cause named to crash when a client sends a flood of HTTP/2
- SETTINGS frames while a DoH response is being written. This affects
- servers with DoH (DNS-over-HTTPS) enabled.
+ Previously, a use-after-free vulnerability in the DNS-over-HTTPS implementation
+ could cause :iscman:`named` to crash when a client sent a flood of HTTP/2
+ SETTINGS frames while a DoH response was being written. This affected
+ servers with DoH (DNS-over-HTTPS) enabled and has been fixed.
ISC would like to thank Naresh Kandula Parmar (Nottiboy) for reporting
- this.
+ this. :gl:`#5755`
+
+- Fix outgoing zone transfers' quota issue.
+
+ Unauthorized clients could consume the entire outgoing zone-transfer quota and
+ block authorized zone transfer clients. This has been fixed.
+ :gl:`#3589`
- For: #5755
Feature Changes
~~~~~~~~~~~~~~~
- Fix CPU spikes and slow queries when cache approaches memory limit.
- Spread cache cleanup probabilistically to avoid CPU usage spikes and a
+ Cache cleanup is now spread probabilistically to avoid CPU usage spikes and a
drop in query throughput. :gl:`#5891`
-- Document that named-checkzone must not run on untrusted input.
-
- The zone-file parser implements $INCLUDE by opening whatever local
- path the zone text names, and fragments of the included file leak
- through parser error messages. There is no safe way to validate
- untrusted zone text with named-checkzone or named-compilezone, so the
- manual pages for both tools now warn against doing so.
+- Implement :rfc:`3645` Section 4.1.1 key expiry check in TKEY.
-- Implement RFC 3645 Section 4.1.1 key expiry check in TKEY.
-
- Check for existing TSIG keys before accepting a new GSS-API
- negotiation and delete the key if it has expired. Previously, an
+ BIND now checks for existing TSIG keys before accepting a new GSS-API
+ negotiation, and deletes the key if it has expired. Previously, an
expired GSS key would permanently block re-negotiation for that name
- until the server was restarted.
+ until the server was restarted. :gl:`!11713`
- Reduce memory footprint by actively returning unused memory to the OS.
is reduced from 10 seconds to 5 seconds. Additionally, a volume-based
decay pass is triggered after every 16 MiB of freed memory. On
glibc-based systems, a similar volume-based mechanism using
- malloc_trim() is used instead.
+ ``malloc_trim()`` is used instead. :gl:`!11761`
Bug Fixes
~~~~~~~~~
- Use the zone file's basename as origin in DNSSEC tools.
- In `dnssec-signzone` and `dnssec-verify`, when the zone origin is not
- specified using the `-o` parameter, the default behavior is to try to
+ In :iscman:`dnssec-signzone` and :iscman:`dnssec-verify`, when the zone origin is not
+ specified using the ``-o`` parameter, the default behavior is to try to
sign using the zone's file name as the origin. So, for example,
- `dnssec-signzone -S example.com` will work, so long as the file name
+ ``dnssec-signzone -S example.com`` will work, so long as the file name
matches the zone name.
This now also works if the zone is in a different directory. For
- example, `dnssec-signzone -S zones/example.com` will set the origin
- value to `example.com`. :gl:`#5678`
+ example, ``dnssec-signzone -S zones/example.com`` will set the origin
+ value to ``example.com``. :gl:`#5678`
- Fix a possible race condition during zone transfers.
processing an IXFR message during a zone transfer. This has been
fixed. :gl:`#5767`
-- Do not resend query after BADCOOKIE answer on TCP.
+- Do not resend query after ``BADCOOKIE`` answer on TCP.
- When an upstream server answers BADCOOKIE, no matter which transport
- is used, the resolver resends the query using TCP. However, if the
- upstream server responded with BADCOOKIE again over TCP, the resolver
+ When an upstream server answered ``BADCOOKIE``, no matter which transport
+ was used, the resolver resent the query using TCP. However, if the
+ upstream server responded with ``BADCOOKIE`` again over TCP, the resolver
would keep resending until the maximum query count was reached.
This is now fixed by no longer resending once the query has already
been sent over TCP. :gl:`#5804`
-- Fix named crash when processing SIG records in dynamic updates.
+- Fix :iscman:`named` crash when processing SIG records in dynamic updates.
Previously, :iscman:`named` could abort if a client sent a dynamic
update containing a SIG record (the legacy signature type) to a zone
configured with an update-policy. The function `dns_db_findrdataset`
had an incorrect requirements prerequisite that prevented SIG records
- being looked up, which was triggered as part of processing an UPDATE
+ from being looked up, which was triggered as part of processing an UPDATE
request and could be triggered remotely by any client permitted to
send updates. This has been fixed by ensuring that SIG records are
handled consistently with RRSIG records during update processing.
When a secondary received an IXFR that transitioned a zone from
unsigned to NSEC-signed, queries for empty non-terminal names returned
- the zone apex NSEC record instead of the NSEC that actually covers the
+ the zone apex NSEC record instead of the NSEC that actually covered the
queried name. The issue only occurred with incremental transfers; a
full AXFR or a server restart resolved it. :gl:`#5824`
-- Fix rndc modzone behavior for a zone in named.conf.
+- Fix :option:`rndc modzone` behavior for a zone in named.conf.
If a zone was present in the configuration file and not originally
- added by `rndc addzone`, `rndc modzone` for that zone would succeed
- once but subsequent `modzone` attempts would fail. This has been
+ added by :option:`rndc addzone`, :option:`rndc modzone` for that zone would succeed
+ once but subsequent :option:`rndc modzone` attempts would fail. This has been
fixed. :gl:`#5826`
- Fix zone verification of NSEC3 signed zones.
Previously, when computing the compressed bitmap during verification
of an NSEC3-signed zone, an undersized buffer was used that resulted
in an out-of-bounds write if there were too many active windows in the
- bitmap. This impacted mirror zones which are NSEC3-signed,
- `dnssec-signzone` and `dnssec-verifyzone`. This has been fixed.
+ bitmap. This impacted the mirror zones which are NSEC3-signed,
+ :iscman:`dnssec-signzone` and :iscman:`dnssec-verify`. This has been fixed.
:gl:`#5834`
-- Fix 'rndc modzone' issue with non-existing zones.
+- Fix :option:`rndc modzone` issue with non-existing zones.
The :iscman:`named` process could terminate unexpectedly or become
subject to undefined behavior when issued an :option:`rndc modzone`
The :iscman:`named` process could terminate unexpectedly when
processing a catalog member zone containing special characters like
- '%' or '$' which could be interpreted as zone filename tokens and
+ "%" or "$", which could be interpreted as zone filename tokens and
trigger a case-sensitivity bug in the token-parsing code. This has
been fixed. :gl:`#5849`
-- Prevent a crash when using both dns64 and filter-aaaa.
+- Prevent a crash when using both :any:`dns64` and :any:`filter-aaaa`.
- An assertion failure could be triggered if both `dns64` and the
- `filter-aaaa` plugin were in use simultaneously. This happened if the
+ An assertion failure could be triggered if both :any:`dns64` and the
+ :any:`filter-aaaa` plugin were in use simultaneously. This happened if the
plugin triggered a second recursion process, which then attempted to
store DNS64 state information in a pointer that had already been set
by the original recursion process. This has been fixed. :gl:`#5854`
-- Remove unnecessary dns_name_free call.
+- Fixed an assertion failure when processing catalog zones.
- When processing a catalog zone member's primaries definition and there
- is a TXT record containing an invalid name TSIG key name,
- dns_name_free was incorrectly called triggering an assertion. This has
+ If a TXT record containing an invalid name TSIG key name was found
+ when processing a catalog zone member's primaries definition,
+ ``dns_name_free`` was incorrectly called, triggering an assertion. This has
been fixed. :gl:`#5858`
- Prevent malicious DNSSEC zones from exhausting validator CPU.
validator now rejects such DNSKEYs, matching the limit already applied
to keys read from files or HSMs. :gl:`#5881`
-- Fix rndc-confgen aborting on HMAC-SHA-384/512 keys above 512 bits.
+- Fix :iscman:`rndc-confgen` aborting on HMAC-SHA-384/512 keys above 512 bits.
- `rndc-confgen -A hmac-sha384` and `-A hmac-sha512` documented a `-b`
+ :iscman:`rndc-confgen` (with either ``-A hmac-sha384`` or
+ ``-A hmac-sha512``) previously documented a ``-b``
range of 1..1024, but any value above 512 aborted on hardened builds
instead of producing a key. The full advertised range now works.
:gl:`#5903`
-- Validate key names in rndc-confgen, tsig-keygen, ddns-confgen.
+- Validate key names in :iscman:`rndc-confgen`, :iscman:`tsig-keygen`, and :iscman:`ddns-confgen`.
The three tools embedded the key-name argument verbatim into the
generated `named.conf` block, so a name containing characters like
placement of entries cannot be predicted or influenced from the
network. :gl:`#5906`
-- Prevent rare named crash when notifies are cancelled.
+- Prevent rare :iscman:`named` crash when notifies are cancelled.
- Under heavy load, named could occasionally crash when a queued
+ Under heavy load, :iscman:`named` could occasionally crash when a queued
outbound notify or zone refresh was cancelled at the moment it was
being sent — for example, while a zone was being reloaded or removed.
The race that caused the crash is now prevented. :gl:`#5915`
-- Stop delv from aborting on a malformed query name.
+- Stop :iscman:`delv` from aborting on a malformed query name.
- delv aborts with SIGABRT instead of exiting cleanly when given a query
- name that fails wire-format conversion (e.g. a label longer than 63
- octets). After this change delv prints the parse error and exits with
+ :iscman:`delv` previously aborted with SIGABRT instead of exiting cleanly when given a query
+ name that failed wire-format conversion (e.g. a label longer than 63
+ octets). After this change :iscman:`delv` prints the parse error and exits with
a normal failure code. :gl:`#5916`
-- Fix dig -x crash on excessively long arguments.
+- Fix :option:`dig -x` crash on excessively long arguments.
- dig -x crashed with a segmentation fault rather than printing an error
- when given an argument with thousands of dot-separated components. dig
- -x now rejects such inputs cleanly with "Invalid IP address".
+ Previously, :option:`dig -x` crashed with a segmentation fault rather than printing
+ an error when given an argument with thousands of dot-separated components.
+ :option:`dig -x` now rejects such inputs cleanly with "Invalid IP address".
:gl:`#5917`
-- Reject negative and out-of-range TTLs in dnssec-* tools.
+- Reject negative and out-of-range TTLs in ``dnssec-*`` tools.
- The dnssec-* tools accepted negative and out-of-range values for TTL
- flags such as dnssec-keygen -L, dnssec-signzone -t and dnssec-settime
- -L, silently turning them into TTLs of around 136 years in the
+ The ``dnssec-*`` tools previously accepted negative and out-of-range values for TTL
+ flags such as :option:`dnssec-keygen -L`, :option:`dnssec-signzone -t`
+ and :option:`dnssec-settime -L`,
+ silently turning them into TTLs of around 136 years in the
resulting key or zone files. The flag values are now validated and
rejected with a clear "TTL must be non-negative" or "TTL out of range"
error. :gl:`#5923`
- Fix a crash when reconfiguring while an NTA is being rechecked.
- When named was reconfigured or shut down while a negative trust anchor
+ Previously, if :iscman:`named` was reconfigured or shut down while a negative trust anchor
was being rechecked against authoritative servers, the in-flight
- recheck could outlive the view that owned it and cause `named` to
+ recheck could outlive the view that owned it and cause :iscman:`named` to
crash. This has been fixed. :gl:`#5938`
-- Fix a bug in allow-query/allow-transfer catalog zone custom
+- Fix a bug in :any:`allow-query`/:any:`allow-transfer` catalog zone custom
properties.
The :iscman:`named` process could terminate unexpectedly when
- processing a catalog zone with an invalid ``allow-query`` or
- ``allow-transfer`` custom property (i.e. having a non-APL type)
+ processing a catalog zone with an invalid :any:`allow-query` or
+ :any:`allow-transfer` custom property (i.e. having a non-APL type)
coexisting with the valid property. This has been fixed. :gl:`#5941`
-- Fix a memory leak issue in the catalog zones.
+- Fix a memory leak issue in catalog zones.
The :iscman:`named` process could leak small amounts of memory when
processing a catalog zone entry which had defined custom primary
- servers with TSIG keys using both the regular ``primaries`` custom
- property syntax and the legacy alternative syntax (``masters``) at the
+ servers with TSIG keys, if both the regular ``primaries`` custom
+ property syntax and the legacy alternative syntax (``masters``) were used at the
same time. This has been fixed. :gl:`#5943`
- Avoid extra round trips for DS lookups when the parent delegation is
already cached.
- DS queries could take two unnecessary extra round trips when the
+ Previously, DS queries could take two unnecessary extra round trips when the
resolver sent them to the child zone instead of the parent. The child
- responds with NODATA, forcing a recovery path to rediscover the parent
- delegation even though it was already cached. The resolver now
+ would respond with NODATA, forcing a recovery path to rediscover the parent
+ delegation even though it was already cached. The resolver now
consults its delegation cache before starting DS fetches, sending
queries directly to the correct parent nameservers and eliminating the
- extra latency.
+ extra latency. :gl:`!11835`
-- Fix suppressed missing-glue check in named-checkzone.
+- Fix suppressed missing-glue check in :iscman:`named-checkzone`.
- named-checkzone and named-checkconf -z silently skipped the
- missing-glue check for any NS name that had already triggered an
- extra-AAAA-glue warning, so zones missing required A glue could pass
- validation and be deployed with broken delegations.
+ :iscman:`named-checkzone` and :option:`named-checkconf -z` silently
+ skipped the missing-glue check for any NS name that had already
+ triggered an extra-AAAA-glue warning, so zones missing required A glue
+ could pass validation and be deployed with broken delegations.
+ :gl:`!11899`
-- Glues from different parent are rejected.
+- Reject glues from different parents.
- The changes making BIND 9 parent-centric !11621 introduced an issue
+ The changes that made BIND 9 parent-centric (!11621) introduced an issue
where it could be possible, when processing a referral, to use the
- glue to a nameserver which has a different parent than the zonecut.
- For instance:
+ glue to direct queries to a nameserver which had a different parent than the zonecut.
+ For instance:::
+
+ AUTHORITY
+ test.example. NS ns.test.example.
+ test.example. NS ns.foo.example.
+ test.example. NS ns.bar.
- AUTHORITY test.example. NS ns.test.example.
- test.example. NS ns.foo.example. test.example.
- NS ns.bar. ADDITIONAL ns.bar.
- A 1.2.3.4 ns.foo.example. A 5.6.7.8
- ns.test.example. A 9.8.7.6
+ ADDITIONAL
+ ns.bar. A 1.2.3.4
+ ns.foo.example. A 5.6.7.8
+ ns.test.example. A 9.8.7.6
- In such situation, only the glues for `ns.foo.example.` and
- `ns.test.example.` should be used, and the glue from `ns.bar.` must be
- ignored as this is not either a sub-domain or a sibling domain, the
- parent is different (`bar.` instead of `example.`). This is now fixed.
+ In such a situation, only the glues for ``ns.foo.example.`` and
+ ``ns.test.example.`` should have been used; the glue from ``ns.bar.`` must be
+ ignored as this is neither a sub-domain nor a sibling domain, and the
+ parent is different (``bar.`` instead of ``example.``). This is now fixed.
- Sibling glue and cyclic sibling glues are defined in RFC 9471 section
- 2.2 and section 2.3.
+ Sibling glue and cyclic sibling glues are defined in :rfc:`9471` section
+ 2.2 and section 2.3. :gl:`!11873`
- Implement seamless outgoing TCP connection reuse.
The resolver can and will reuse outgoing TCP connections to the same
- host, as recommended by RFC 7766. This prevents a whole class of
+ host, as recommended by :rfc:`7766`. This prevents a whole class of
attacks that abuse the fact that establishing a TCP connection is
expensive and it is fairly easy to deplete the outgoing TCP ports by
- putting them into TIME_WAIT state.
+ putting them into ``TIME_WAIT`` state.
The number of pipelined queries per connection is capped at 256 to
- limit the impact of a connection drop.
+ limit the impact of a connection drop. :gl:`!11845`
-- Possible crash when a resolver validate a static-stub zone.
+- Prevent possible crash when a resolver validates a static-stub zone.
A NULL pointer dereference could be made in some circumstances when
resolving and validating a name under a `static-stub` zone. This is
- now fixed.
+ now fixed. :gl:`!11788`
- Prevent excessive priming queries to the root servers.
recursive lookup instead of only when the cached root information
expired. Priming now rearms only after the TTL of the fetched records
elapses, and the refreshed root NS set is used for query routing until
- the next cycle.
+ the next cycle. :gl:`!11847`
- Reject record sets too large to serve in DNS.
- When BIND was asked to store a record set whose total size exceeds
- what fits in a DNS message, it would allocate memory and build the
+ When BIND was asked to store a record set whose total size exceeded
+ what fit in a DNS message, it would allocate memory and build the
structure, then fail later at response time. Such oversized record
sets are now rejected at the time of storage with an error, avoiding
- wasted work on data that can never be served.
+ wasted work on data that can never be served. :gl:`!11963`
-- Stop rndc-confgen from following symlinks when writing the keyfile.
+- Stop :iscman:`rndc-confgen` from following symlinks when writing the
+ keyfile.
- When rndc-confgen -a (re)created the rndc control key, it followed a
- symbolic link if one happened to exist at the keyfile path: the
- existence check looked through the link, then the file was truncated,
+ When :option:`rndc-confgen -a` (re)created the rndc control key, it
+ followed a symbolic link if one happened to exist at the keyfile path;
+ the existence check looked through the link, then the file was truncated,
its ownership changed, and the key contents written into whatever file
- the link pointed at. rndc-confgen now refuses to follow symbolic links
- at the keyfile path and fails with an error instead, so the wrong file
- can no longer be overwritten by accident.
+ the link pointed at. :iscman:`rndc-confgen` now refuses to follow symbolic
+ links at the keyfile path and fails with an error instead, so the wrong
+ file can no longer be overwritten by accident. :gl:`!11902`
projects / thirdparty / bind9.git / commitdiff
