diff --git a/ChangeLog b/ChangeLog
index 01cdced1e5..c92347e427 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Dec 22 19:26:35 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* object.c (rb_mod_const_get): check more strictly.  [ruby-dev:46748]
+	  [Bug #7573]
+
 Wed Dec 19 02:34:48 2012  CHIKANAGA Tomoyuki  <nagachika@ruby-lang.org>
 
 	* cont.c (rb_fiber_start): in case of jump with TAG_FATAL,
diff --git a/object.c b/object.c
index 13765bc621..b385135019 100644
--- a/object.c
+++ b/object.c
@@ -1959,7 +1959,7 @@ rb_mod_const_get(int argc, VALUE *argv, VALUE mod)
 	rb_raise(rb_eNameError, "wrong constant name %s", path);
     }
 
-    if (p[0] == ':' && p[1] == ':') {
+    if (p + 2 < pend && p[0] == ':' && p[1] == ':') {
 	mod = rb_cObject;
 	p += 2;
 	pbeg = p;
@@ -1981,8 +1981,8 @@ rb_mod_const_get(int argc, VALUE *argv, VALUE mod)
 	else {
 	    part = rb_str_subseq(name, pbeg-path, p-pbeg);
 	}
-	if (p[0] == ':') {
-	    if (p[1] != ':') {
+	if (p < pend && p[0] == ':') {
+	    if (p + 2 >= pend || p[1] != ':') {
 		rb_raise(rb_eNameError, "wrong constant name %s", path);
             }
 	    p += 2;
diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index eb1477893b..84dedb431b 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -246,8 +246,9 @@ class TestModule < Test::Unit::TestCase
       ":Object",
       "",
       ":",
-    ].each do |name|
-      e = assert_raises(NameError) {
+      ["String::", "[Bug #7573]"],
+    ].each do |name, msg|
+      e = assert_raises(NameError, "#{msg}#{': ' if msg}wrong constant name #{name.dump}") {
         Object.const_get name
       }
       assert_equal("wrong constant name %s" % name, e.message)