diff --git a/core/authentication_api.php b/core/authentication_api.php
index 140a7fb7bb..5fd48e48c5 100644
--- a/core/authentication_api.php
+++ b/core/authentication_api.php
@@ -6,7 +6,7 @@
 	# See the README and LICENSE files for details
 
 	# --------------------------------------------------------
-	# $Id: authentication_api.php,v 1.61 2007-10-14 19:07:36 nuclear_eclipse Exp $
+	# $Id: authentication_api.php,v 1.62 2007-10-19 06:53:24 vboctor Exp $
 	# --------------------------------------------------------
 
 	require_once( dirname( __FILE__ ) . DIRECTORY_SEPARATOR . 'gpc_api.php' );
@@ -205,6 +205,13 @@ function auth_does_password_match( $p_user_id, $p_test_password ) {
 
 			# pass the stored password in as the salt
 			if ( auth_process_plain_password( $p_test_password, $t_password, $t_login_method ) == $t_password ) {
+				# Do not support migration to PLAIN, since this would be a crazy thing to do.
+				# Also if we do, then a user will be able to login by providing the MD5 value
+				# that is copied from the database.  See #8467 for more details.
+				if ( $t_configured_login_method != PLAIN && $t_login_method == PLAIN ) {
+					continue;
+				}
+
 				# Check for migration to another login method and test whether the password was encrypted
 				# with our previously insecure implemention of the CRYPT method
 				if ( ( $t_login_method != $t_configured_login_method ) ||