diff --git a/CHANGES b/CHANGES
index 0b83c6f118..b923a0a23b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+5659.	[bug]		'W' in wildcard expansions was being mapped to '\000'.
+			[GL #2779]
+
 5658.	[bug]		Increasing "max-cache-size" for a running named instance
 			(using "rndc reconfig") was not causing the hash tables
 			used by cache databases to be grown accordingly. This
diff --git a/bin/tests/system/wildcard/tests.sh b/bin/tests/system/wildcard/tests.sh
index f94f1b16fa..ce5e1d025f 100644
--- a/bin/tests/system/wildcard/tests.sh
+++ b/bin/tests/system/wildcard/tests.sh
@@ -239,5 +239,40 @@ grep "ANSWER: 0," dig.out.ns1.test$n > /dev/null || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
+n=`expr $n + 1`
+echo_i "check wild card expansions by code point ($n)"
+ret=0
+i=0
+while test $i -lt 256
+do
+	x=`expr 00$i : '.*\(...\)$'`
+	$DIG $DIGOPTS @10.53.0.1 "\\$x.example" TXT > dig.out.ns1.$x.test$n
+	if test $i -le 32 -o $i -ge 127
+	then
+		grep '^\\'"$x"'\.example\..*TXT.*\"this is a wildcard\"$' dig.out.ns1.$x.test$n > /dev/null || { echo_i "code point $x failed" ; ret=1; }
+        # "=34 $=36 (=40 )=41 .=46 ;=59 \=92 @=64
+	elif test $i -eq 34 -o $i -eq 36 -o $i -eq 40 -o $i -eq 41 -o \
+                  $i -eq 46 -o $i -eq 59 -o $i -eq 64 -o $i -eq 92
+	then
+		case $i in
+		34) a='"';;
+		36) a='$';;
+		40) a='(';;
+		41) a=')';;
+		46) a='\.';;
+		59) a=';';;
+		64) a='@';;
+		92) a='\\';;
+		*) a=''; echo_i "code point $x failed" ; ret=1 ;;
+		esac
+		grep '^\\'"$a"'\.example.*.*TXT.*"this is a wildcard"$' dig.out.ns1.$x.test$n > /dev/null || { echo_i "code point $x failed" ; ret=1; }
+	else
+		grep '^\\' dig.out.ns1.$x.test$n && { echo_i "code point $x failed" ; ret=1; }
+	fi
+	i=`expr $i + 1`
+done
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
 echo_i "exit status: $status"
 [ $status -eq 0 ] || exit 1
diff --git a/doc/notes/notes-current.rst b/doc/notes/notes-current.rst
index f553c45c76..114c25afe6 100644
--- a/doc/notes/notes-current.rst
+++ b/doc/notes/notes-current.rst
@@ -48,3 +48,8 @@ Bug Fixes
   lacked the necessary NSEC records or contained duplicate NSEC records
   when both wildcard expansion and CNAME chaining were required to
   prepare the response. This has been fixed. :gl:`#2759`
+
+- Queries where the wildcard match contained the letter ``W`` failed
+  to return the correct response as the ``W`` was mapped to ``\000``.
+  :gl:`#2779`
+
diff --git a/lib/dns/rbtdb.c b/lib/dns/rbtdb.c
index 11bd4712d9..06ac91d793 100644
--- a/lib/dns/rbtdb.c
+++ b/lib/dns/rbtdb.c
@@ -9874,7 +9874,8 @@ static const unsigned char maptolower[256] = {
 	['F'] = 'f', ['G'] = 'g', ['H'] = 'h', ['I'] = 'i', ['J'] = 'j',
 	['K'] = 'k', ['L'] = 'l', ['M'] = 'm', ['N'] = 'n', ['O'] = 'o',
 	['P'] = 'p', ['Q'] = 'q', ['R'] = 'r', ['S'] = 's', ['T'] = 't',
-	['U'] = 'u', ['V'] = 'v', ['X'] = 'x', ['Y'] = 'y', ['Z'] = 'z',
+	['U'] = 'u', ['V'] = 'v', ['W'] = 'w', ['X'] = 'x', ['Y'] = 'y',
+	['Z'] = 'z',
 };
 
 static const unsigned char maptoupper[256] = {
@@ -9882,7 +9883,8 @@ static const unsigned char maptoupper[256] = {
 	['f'] = 'F', ['g'] = 'G', ['h'] = 'H', ['i'] = 'I', ['j'] = 'J',
 	['k'] = 'K', ['l'] = 'L', ['m'] = 'M', ['n'] = 'N', ['o'] = 'O',
 	['p'] = 'P', ['q'] = 'Q', ['r'] = 'R', ['s'] = 'S', ['t'] = 'T',
-	['u'] = 'U', ['v'] = 'V', ['x'] = 'X', ['y'] = 'Y', ['z'] = 'Z',
+	['u'] = 'U', ['v'] = 'V', ['w'] = 'W', ['x'] = 'X', ['y'] = 'Y',
+	['z'] = 'Z',
 };
 
 static void