--- /dev/null
+.. 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 9.20.21
+----------------------
+
+Security Fixes
+~~~~~~~~~~~~~~
+
+- [CVE-2026-1519] Fix unbounded NSEC3 iterations when validating
+ referrals to unsigned delegations.
+
+ DNSSEC-signed zones may contain high iteration-count NSEC3 records,
+ which prove that certain delegations are insecure. Previously, a
+ validating resolver encountering such a delegation processed these
+ iterations up to the number given, which could be a maximum of 65,535.
+ This has been addressed by introducing a processing limit, set at 50.
+ Now, if such an NSEC3 record is encountered, the delegation will be
+ treated as insecure.
+
+ ISC would like to thank Samy Medjahed/Ap4sh for bringing this
+ vulnerability to our attention. :gl:`#5708`
+
+- [CVE-2026-3104] Fix memory leaks in code preparing DNSSEC proofs of
+ non-existence.
+
+ An attacker controlling a DNSSEC-signed zone could trigger a memory
+ leak in the logic preparing DNSSEC proofs of non-existence, by
+ creating more than :any:`max-records-per-type` RRSIGs for NSEC
+ records. These memory leaks have been fixed.
+
+ ISC would like to thank Vitaly Simonovich for bringing this
+ vulnerability to our attention. :gl:`#5742`
+
+- [CVE-2026-3119] Prevent a crash in code processing queries containing
+ a TKEY record.
+
+ The :iscman:`named` process could terminate unexpectedly when
+ processing a correctly signed query containing a TKEY record. This has
+ been fixed.
+
+ ISC would like to thank Vitaly Simonovich for bringing this
+ vulnerability to our attention. :gl:`#5748`
+
+- [CVE-2026-3591] Fix a stack use-after-return flaw in SIG(0) handling
+ code.
+
+ A stack use-after-return flaw in SIG(0) handling code could enable ACL
+ bypass and/or assertion failures in certain circumstances. This flaw
+ has been fixed.
+
+ ISC would like to thank Mcsky23 for bringing this vulnerability to our
+ attention. :gl:`#5754`
+
+Bug Fixes
+~~~~~~~~~
+
+- Resolve "key defined in view is not found"
+
+ Commit `2956e4fc` hardened the `key` name check when used in
+ `primaries` to reject the configuration if the key was not defined,
+ rather than simply checking whether the key name was correctly formed.
+
+ However, the key name check didn't include the view configuration,
+ causing keys not to be recognized if they were defined inside the view
+ and not at the global level. This regression is now fixed.
+ :gl:`#5761`
+
+