diff --git a/ext/standard/tests/url/bug74780.phpt b/ext/standard/tests/url/bug74780.phpt
new file mode 100644
index 0000000000000..ae464d971b084
--- /dev/null
+++ b/ext/standard/tests/url/bug74780.phpt
@@ -0,0 +1,38 @@
+--TEST--
+Bug #74780	parse_url() borks when query string contains colon
+--FILE--
+<?php
+var_dump(
+    parse_url('//php.net/path?query=1:2'),
+    parse_url('//php.net/path.php?query=a:b'),
+    parse_url('//username@php.net/path?query=1:2')
+);
+
+?>
+--EXPECT--
+array(3) {
+  ["host"]=>
+  string(7) "php.net"
+  ["path"]=>
+  string(5) "/path"
+  ["query"]=>
+  string(9) "query=1:2"
+}
+array(3) {
+  ["host"]=>
+  string(7) "php.net"
+  ["path"]=>
+  string(9) "/path.php"
+  ["query"]=>
+  string(9) "query=a:b"
+}
+array(4) {
+  ["host"]=>
+  string(7) "php.net"
+  ["user"]=>
+  string(8) "username"
+  ["path"]=>
+  string(5) "/path"
+  ["query"]=>
+  string(9) "query=1:2"
+}
\ No newline at end of file
diff --git a/ext/standard/url.c b/ext/standard/url.c
index 86f8c45563d29..9c42afbdeac72 100644
--- a/ext/standard/url.c
+++ b/ext/standard/url.c
@@ -112,6 +112,10 @@ PHPAPI php_url *php_url_parse_ex(char const *str, size_t length)
 			if (!isalpha(*p) && !isdigit(*p) && *p != '+' && *p != '.' && *p != '-') {
 				if (e + 1 < ue && e < s + strcspn(s, "?#")) {
 					goto parse_port;
+				} else if (s + 1 < ue && *s == '/' && *(s + 1) == '/') { /* relative-scheme URL */
+					s += 2;
+					e = 0;
+					goto parse_host;
 				} else {
 					goto just_path;
 				}
@@ -208,6 +212,7 @@ PHPAPI php_url *php_url_parse_ex(char const *str, size_t length)
 		goto just_path;
 	}
 
+	parse_host:
 	/* Binary-safe strcspn(s, "/?#") */
 	e = ue;
 	if ((p = memchr(s, '/', e - s))) {