diff --git a/app/assets/javascripts/import_entities/import_groups/constants.js b/app/assets/javascripts/import_entities/import_groups/constants.js
index 870544fca9228e6627c680c0587ecd846b344c55..ea3ee1fe69c167bd9dd883141409304ef0408da1 100644
--- a/app/assets/javascripts/import_entities/import_groups/constants.js
+++ b/app/assets/javascripts/import_entities/import_groups/constants.js
@@ -128,3 +128,9 @@ export const PLACEHOLDER_SORT_STATUS_DESC = 'STATUS_DESC';
 export const PLACEHOLDER_SORT_STATUS_ASC = 'STATUS_ASC';
 export const PLACEHOLDER_SORT_SOURCE_NAME_ASC = 'SOURCE_NAME_ASC';
 export const PLACEHOLDER_SORT_SOURCE_NAME_DESC = 'SOURCE_NAME_DESC';
+export const PLACEHOLDER_SORT_VALUES = [
+  PLACEHOLDER_SORT_STATUS_DESC,
+  PLACEHOLDER_SORT_STATUS_ASC,
+  PLACEHOLDER_SORT_SOURCE_NAME_ASC,
+  PLACEHOLDER_SORT_SOURCE_NAME_DESC,
+];
diff --git a/app/assets/javascripts/members/placeholders/components/app.vue b/app/assets/javascripts/members/placeholders/components/app.vue
index cfdfa90a227668ebed139fd8d4744e5d23a3ea74..366fdbe1e2712ef24d44daae7912f70793ec51cb 100644
--- a/app/assets/javascripts/members/placeholders/components/app.vue
+++ b/app/assets/javascripts/members/placeholders/components/app.vue
@@ -32,6 +32,7 @@ import {
   PLACEHOLDER_SORT_STATUS_ASC,
   PLACEHOLDER_SORT_SOURCE_NAME_ASC,
   PLACEHOLDER_SORT_SOURCE_NAME_DESC,
+  PLACEHOLDER_SORT_VALUES,
   PLACEHOLDER_TAB_AWAITING,
   PLACEHOLDER_TAB_REASSIGNED,
 } from '~/import_entities/import_groups/constants';
@@ -198,7 +199,7 @@ export default {
 
       this.filterParams = { ...queryParams };
 
-      if (sort) {
+      if (sort && PLACEHOLDER_SORT_VALUES.includes(sort)) {
         this.sort = sort || PLACEHOLDER_SORT_SOURCE_NAME_ASC;
       }
 
diff --git a/spec/frontend/members/placeholders/components/app_spec.js b/spec/frontend/members/placeholders/components/app_spec.js
index d686ff99689aa241c92e8ba299cff801ba5d2573..31f41db3077f5b7c554ee0e3bcbb091410e3c76d 100644
--- a/spec/frontend/members/placeholders/components/app_spec.js
+++ b/spec/frontend/members/placeholders/components/app_spec.js
@@ -141,6 +141,17 @@ describe('PlaceholdersTabApp', () => {
       });
     });
 
+    describe('with invalid sort query', () => {
+      beforeEach(() => {
+        setWindowLocation('?sort=last_joined');
+        createComponent();
+      });
+
+      it('falls back to default sort for FilteredSearchBar', () => {
+        expect(findFilteredSearchBar().props('initialSortBy')).toBe('SOURCE_NAME_ASC');
+      });
+    });
+
     describe('with status, search and sort queries present on load', () => {
       beforeEach(() => {
         setWindowLocation('?status=failed&search=foo&sort=STATUS_ASC');