From: Michał Kępień <michal@isc.org>
Date: Thu, 26 Feb 2026 20:17:47 +0000 (+0100)
Subject: Add release note for GL !11563
X-Git-Tag: v9.21.19~1^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=56bf659a4b6f381c01928f41066da27c91a0cbf8;p=thirdparty%2Fbind9.git

Add release note for GL !11563
---

diff --git a/doc/notes/notes-9.21.19.rst b/doc/notes/notes-9.21.19.rst
index 30dc4a57538..b487fed8423 100644
--- a/doc/notes/notes-9.21.19.rst
+++ b/doc/notes/notes-9.21.19.rst
@@ -99,3 +99,11 @@ Bug Fixes
   the import function might overflow. This could lead to a memory
   corruption on the stack and ultimately a server crash. This has been
   fixed. :gl:`#5758`
+
+- Return FORMERR for queries with the EDNS Client Subnet FAMILY field
+  set to 0.
+
+  :rfc:`7871` only defines families 1 (IPv4) and 2 (IPv6), and requires
+  FORMERR to be returned for all unknown families. Queries with the EDNS
+  Client Subnet FAMILY field set to 0 now elicit responses with
+  RCODE=FORMERR. :gl:`!11563`