diff --git a/news/4601.bugfix b/news/4601.bugfix
new file mode 100644
index 0000000000..cbb24473ca
--- /dev/null
+++ b/news/4601.bugfix
@@ -0,0 +1 @@
+Fix regexp that checks valid URLs and improve tests [cekk]
diff --git a/src/helpers/FormValidation/FormValidation.js b/src/helpers/FormValidation/FormValidation.js
index 7c6d609f19..0c5fd28eac 100644
--- a/src/helpers/FormValidation/FormValidation.js
+++ b/src/helpers/FormValidation/FormValidation.js
@@ -65,7 +65,16 @@ const widgetValidation = {
   },
   url: {
     isValidURL: (urlValue, urlObj, intlFunc) => {
-      const urlRegex = /^(http:\/\/www\.|https:\/\/www\.|http:\/\/|https:\/\/)?[a-z0-9]+([-.]{1}[a-z0-9]+)*\.[a-z]{2,5}(:[0-9]{1,5})?(\/.*)?|^(http:\/\/www\.|https:\/\/www\.|http:\/\/|https:\/\/)?[a-z0-9]+([_.]{1}[a-z0-9]+)*\.[a-z]{2,5}(:[0-9]{1,5})?(\/.*)?|^((http:\/\/www\.|https:\/\/www\.|http:\/\/|https:\/\/)?([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/gm;
+      var urlRegex = new RegExp(
+        '^(https?:\\/\\/)?' + // validate protocol
+        '((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|' + // validate domain name
+        '((\\d{1,3}\\.){3}\\d{1,3}))|' + // validate OR ip (v4) address
+        '(localhost)' + // validate OR localhost address
+        '(\\:\\d+)?(\\/[-a-z\\d%_.~+]*)*' + // validate port and path
+        '(\\?[;&a-z\\d%_.~+=-]*)?' + // validate query string
+          '(\\#[-a-z\\d_]*)?$', // validate fragment locator
+        'i',
+      );
       const isValid = urlRegex.test(urlValue);
       return !isValid ? intlFunc(messages.isValidURL) : null;
     },
diff --git a/src/helpers/FormValidation/FormValidation.test.js b/src/helpers/FormValidation/FormValidation.test.js
index 56da3a43a3..df25ac0038 100644
--- a/src/helpers/FormValidation/FormValidation.test.js
+++ b/src/helpers/FormValidation/FormValidation.test.js
@@ -5,6 +5,7 @@ const schema = {
   properties: {
     username: { title: 'Username', type: 'string', description: '' },
     email: { title: 'Email', type: 'string', widget: 'email', description: '' },
+    url: { title: 'url', type: 'string', widget: 'url', description: '' },
   },
   fieldsets: [
     { id: 'default', title: 'FIXME: User Data', fields: ['username'] },
@@ -87,5 +88,45 @@ describe('FormValidation', () => {
         }),
       ).toEqual({});
     });
+    it('validates incorrect url', () => {
+      formData.url = 'foo';
+      expect(
+        FormValidation.validateFieldsPerFieldset({
+          schema,
+          formData,
+          formatMessage,
+        }),
+      ).toEqual({ url: [messages.isValidURL.defaultMessage] });
+    });
+    it('validates url', () => {
+      formData.url = 'https://plone.org/';
+      expect(
+        FormValidation.validateFieldsPerFieldset({
+          schema,
+          formData,
+          formatMessage,
+        }),
+      ).toEqual({});
+    });
+    it('validates url with ip', () => {
+      formData.url = 'http://127.0.0.1:8080/Plone';
+      expect(
+        FormValidation.validateFieldsPerFieldset({
+          schema,
+          formData,
+          formatMessage,
+        }),
+      ).toEqual({});
+    });
+    it('validates url with localhost', () => {
+      formData.url = 'http://localhost:8080/Plone';
+      expect(
+        FormValidation.validateFieldsPerFieldset({
+          schema,
+          formData,
+          formatMessage,
+        }),
+      ).toEqual({});
+    });
   });
 });