diff --git a/includes/AbuseFilter.php b/includes/AbuseFilter.php
index 45ad97eba..b182c5373 100644
--- a/includes/AbuseFilter.php
+++ b/includes/AbuseFilter.php
@@ -1577,6 +1577,9 @@ class AbuseFilter {
 				if ( !$wgUser->isAnon() ) {
 					// Remove all groups from the user.
 					$groups = $wgUser->getGroups();
+					// Make sure that the stored var dump contains user groups, since we may
+					// need them if reverting this degroup via Special:AbuseFilter/revert
+					$vars->setVar( 'user_groups', $groups );
 
 					foreach ( $groups as $group ) {
 						$wgUser->removeGroup( $group );
diff --git a/includes/Views/AbuseFilterViewRevert.php b/includes/Views/AbuseFilterViewRevert.php
index 446eae86a..ab48d6966 100644
--- a/includes/Views/AbuseFilterViewRevert.php
+++ b/includes/Views/AbuseFilterViewRevert.php
@@ -269,8 +269,7 @@ class AbuseFilterViewRevert extends AbuseFilterView {
 				return true;
 			case 'degroup':
 				// Pull the user's groups from the vars.
-				$oldGroups = $result['vars']['USER_GROUPS'];
-				$oldGroups = explode( ',', $oldGroups );
+				$oldGroups = $result['vars']->getVar( 'user_groups' )->toNative();
 				$oldGroups = array_diff(
 					$oldGroups,
 					array_intersect( $oldGroups, User::getImplicitGroups() )