diff --git a/ext/sockets/conversions.c b/ext/sockets/conversions.c
index e5894a1de83..b4a13f39cd9 100644
--- a/ext/sockets/conversions.c
+++ b/ext/sockets/conversions.c
@@ -611,7 +611,7 @@ static void from_zval_write_sin6_addr(const zval *zaddr_str, char *addr6, ser_co
 	} else {
 		/* error already emitted, but let's emit another more relevant */
 		do_from_zval_err(ctx, "could not resolve address '%s' to get an AF_INET6 "
-				"address", Z_STRVAL_P(zaddr_str));
+				"address", ZSTR_VAL(addr_str));
 	}
 
 	zend_tmp_string_release(tmp_addr_str);
diff --git a/ext/sockets/tests/gh21161.phpt b/ext/sockets/tests/gh21161.phpt
new file mode 100644
index 00000000000..8a3958a583d
--- /dev/null
+++ b/ext/sockets/tests/gh21161.phpt
@@ -0,0 +1,19 @@
+--TEST--
+GH-21161 (IPV6_PKTINFO socket option crash with null addr array entry)
+--EXTENSIONS--
+sockets
+--SKIPIF--
+<?php
+if (substr(PHP_OS, 0, 3) == 'WIN') {
+    die('skip.. Not valid for Windows');
+}
+?>
+--FILE--
+<?php
+$sock = socket_create(AF_INET6, SOCK_DGRAM, 0);
+socket_set_option($sock, IPPROTO_IPV6, IPV6_PKTINFO, ['addr' => null, 'ifindex' => 0]);
+?>
+--EXPECTF--
+Warning: socket_set_option(): Host lookup failed [%i]: %s on line %d
+
+Warning: socket_set_option(): error converting user data (path: in6_pktinfo > addr): could not resolve address '' to get an AF_INET6 address in %s on line %d