diff --git a/ext/soap/php_http.c b/ext/soap/php_http.c
index 0bec42afbc37..e9fd68007d26 100644
--- a/ext/soap/php_http.c
+++ b/ext/soap/php_http.c
@@ -1151,8 +1151,10 @@ int make_http_soap_request(zval        *this_ptr,
 				zend_string_release_ex(http_body, 0);
 				if (new_url->scheme == NULL && new_url->path != NULL) {
 					new_url->scheme = phpurl->scheme ? zend_string_copy(phpurl->scheme) : NULL;
-					new_url->host = phpurl->host ? zend_string_copy(phpurl->host) : NULL;
-					new_url->port = phpurl->port;
+					if (new_url->host == NULL) {
+						new_url->host = phpurl->host ? zend_string_copy(phpurl->host) : NULL;
+						new_url->port = phpurl->port;
+					}
 					if (new_url->path && ZSTR_VAL(new_url->path)[0] != '/') {
 						if (phpurl->path) {
 							char *t = ZSTR_VAL(phpurl->path);
diff --git a/ext/soap/tests/bugs/protocol_relative_redirect.phpt b/ext/soap/tests/bugs/protocol_relative_redirect.phpt
new file mode 100644
index 000000000000..e8f30ca66872
--- /dev/null
+++ b/ext/soap/tests/bugs/protocol_relative_redirect.phpt
@@ -0,0 +1,49 @@
+--TEST--
+SOAP client follows a protocol-relative (//host/path) redirect Location without leaking the host
+--EXTENSIONS--
+soap
+--SKIPIF--
+<?php
+if (!file_exists(__DIR__ . "/../../../../sapi/cli/tests/php_cli_server.inc")) {
+    echo "skip sapi/cli/tests/php_cli_server.inc required but not found";
+}
+?>
+--FILE--
+<?php
+include __DIR__ . "/../../../../sapi/cli/tests/php_cli_server.inc";
+
+$args = ["-d", "extension_dir=" . ini_get("extension_dir"), "-d", "extension=" . (substr(PHP_OS, 0, 3) == "WIN" ? "php_" : "") . "soap." . PHP_SHLIB_SUFFIX];
+if (php_ini_loaded_file()) {
+    $args[] = "-c";
+    $args[] = php_ini_loaded_file();
+}
+
+$code = <<<'PHP'
+if ($_SERVER["REQUEST_URI"] === "/redirected") {
+    header("Content-Type: text/xml; charset=utf-8");
+    echo '<?xml version="1.0" encoding="UTF-8"?>',
+        '<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">',
+        '<SOAP-ENV:Body><fooResponse><result>ok</result></fooResponse></SOAP-ENV:Body>',
+        '</SOAP-ENV:Envelope>';
+} else {
+    http_response_code(302);
+    header("Location: //" . $_SERVER["HTTP_HOST"] . "/redirected");
+}
+PHP;
+
+php_cli_server_start($code, null, $args);
+
+$client = new SoapClient(null, [
+    'location' => 'http://' . PHP_CLI_SERVER_ADDRESS . '/start',
+    'uri' => 'test-uri',
+]);
+
+try {
+    $client->__soapCall("foo", []);
+    echo "redirect followed\n";
+} catch (SoapFault $e) {
+    echo "SoapFault: " . $e->getMessage() . "\n";
+}
+?>
+--EXPECT--
+redirect followed