From 6a65bf467b1aacdc66ad775797f7ece9ba652d19 Mon Sep 17 00:00:00 2001 From: Andoni Duarte Pintado Date: Fri, 8 May 2026 10:24:43 +0200 Subject: [PATCH] Prepare release notes for BIND 9.20.23 --- doc/arm/notes.rst | 1 + doc/notes/notes-9.20.23.rst | 246 ++++++++++++++++++++++++++++++++++++ 2 files changed, 247 insertions(+) create mode 100644 doc/notes/notes-9.20.23.rst diff --git a/doc/arm/notes.rst b/doc/arm/notes.rst index d5b88c559c..a91b6c7d90 100644 --- a/doc/arm/notes.rst +++ b/doc/arm/notes.rst @@ -45,6 +45,7 @@ The list of known issues affecting the latest version in the 9.20 branch can be found at https://gitlab.isc.org/isc-projects/bind9/-/wikis/Known-Issues-in-BIND-9.20 +.. include:: ../notes/notes-9.20.23.rst .. include:: ../notes/notes-9.20.22.rst .. include:: ../notes/notes-9.20.21.rst .. include:: ../notes/notes-9.20.20.rst diff --git a/doc/notes/notes-9.20.23.rst b/doc/notes/notes-9.20.23.rst new file mode 100644 index 0000000000..1cbe34c8ac --- /dev/null +++ b/doc/notes/notes-9.20.23.rst @@ -0,0 +1,246 @@ +.. Copyright (C) Internet Systems Consortium, Inc. ("ISC") +.. +.. SPDX-License-Identifier: MPL-2.0 +.. +.. This Source Code Form is subject to the terms of the Mozilla Public +.. License, v. 2.0. If a copy of the MPL was not distributed with this +.. file, you can obtain one at https://mozilla.org/MPL/2.0/. +.. +.. See the COPYRIGHT file distributed with this work for additional +.. information regarding copyright ownership. + +Notes for BIND 9.20.23 +---------------------- + +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` + +- [CVE-2026-3592] Limit resolver server list size. + + When resolving a domain with many nameservers that share 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 + 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` + +- [CVE-2026-3039] Fix GSS-API resource leak. + + Fixed a memory leak 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 + 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. + + Also implemented missing RFC 3645 requirement: the client now verifies + that mutual authentication and integrity flags are granted by the + GSS-API mechanism (Section 3.1.1). :gl:`#5752` + +- [CVE-2026-5950] Avoid unbounded recursion loop. + + A bug during bad server handling could cause the resolver to enter an + infinite loop, continuously sending queries to an upstream server with + no exit condition, until the resolver query timeout was hit. This has + been fixed. + + ISC would like to thank Billy Baraja (BielraX) for bringing this issue + to our attention. :gl:`#5804` + +- [CVE-2026-3593] Add system test for HTTP/2 SETTINGS frame flood. + + 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. + + ISC would like to thank Naresh Kandula Parmar (Nottiboy) for reporting + this. + + For: #5755 + +- [CVE-2026-5946] Disable recursion, UPDATE, and NOTIFY for non-IN + views. + + 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 + NOTIFY messages that specify the meta-classes ANY or NONE in the + question section are now rejected with FORMERR. + + This addresses a set of closely related security issues collectively + identified as CVE-2026-5946. ISC would like to thank Mcsky23 for + bringing these issues to our attention. + +Feature Changes +~~~~~~~~~~~~~~~ + +- Fix CPU spikes and slow queries when cache approaches memory limit. + + When the cache grew close to the configured max-cache-size, every + subsequent entry triggered all worker threads to run cache cleanup at + once, causing CPU spikes and a drop in query throughput. Cleanup is + now spread probabilistically across inserts as memory approaches the + limit, so the work is distributed evenly instead of piling up at the + threshold. + +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 + 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 + 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` + +- Fix a possible race condition during zone transfers. + + The :iscman:`named` process could terminate unexpectedly when + processing an IXFR message during a zone transfer. This has been + fixed. :gl:`#5767` + +- Fix 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 + 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. + :gl:`#5818` + +- 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. + :gl:`#5834` + +- Prevent a crash when using both dns64 and filter-aaaa. + + An assertion failure could be triggered if both `dns64` and the + `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. + + 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 + been fixed. :gl:`#5858` + +- Prevent malicious DNSSEC zones from exhausting validator CPU. + + A DNSSEC-signed zone could publish a DNSKEY with an unusually large + RSA public exponent and force any validator resolving names in that + zone to spend disproportionate CPU verifying signatures. The + 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. + + `rndc-confgen -A hmac-sha384` and `-A hmac-sha512` 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` + +- Prevent crafted queries from degrading RRL performance. + + With response rate limiting enabled, an attacker sending queries from + many spoofed source addresses could steer entries into the same slot + of the internal rate-limit table and slow down query processing on the + affected server. The table now uses a per-process keyed hash so the + placement of entries cannot be predicted or influenced from the + network. :gl:`#5906` + +- Prevent rare named crash when notifies are cancelled. + + Under heavy load, 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. + + 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 + a normal failure code. :gl:`#5916` + +- Fix a crash when reconfiguring while an NTA is being rechecked. + + When 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 + crash. This has been fixed. :gl:`#5938` + +- Fix a bug in allow-query/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) + coexisting with the valid property. This has been fixed. :gl:`#5941` + +- Fix a memory leak issue in the 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 + same time. This has been fixed. :gl:`#5943` + +- Fix suppressed missing-glue check in 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. + +- 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 + 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. + + The number of pipelined queries per connection is capped at 256 to + limit the impact of a connection drop. + +- 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 + 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. + +