diff --git a/typo3/sysext/backend/Classes/Form/Element/InputLinkElement.php b/typo3/sysext/backend/Classes/Form/Element/InputLinkElement.php
index c02f23f73eb3391e06da5f8362324e1ec8af200c..c43b822ba2ee68636d563e14959291804f376136 100644
--- a/typo3/sysext/backend/Classes/Form/Element/InputLinkElement.php
+++ b/typo3/sysext/backend/Classes/Form/Element/InputLinkElement.php
@@ -446,7 +446,7 @@ class InputLinkElement extends AbstractFormElement
     protected function getDomainByUrl(string $uriString): string
     {
         $data = parse_url($uriString);
-        return $data['host'] ?? '';
+        return $data['host'] ?? $uriString;
     }
 
     /**
diff --git a/typo3/sysext/core/Classes/LinkHandling/LinkService.php b/typo3/sysext/core/Classes/LinkHandling/LinkService.php
index 950349f8158ff5179bc1b357eeef6bf5f41ffb72..56595c142517c306d8e2c0f64fe866695cae9e5a 100644
--- a/typo3/sysext/core/Classes/LinkHandling/LinkService.php
+++ b/typo3/sysext/core/Classes/LinkHandling/LinkService.php
@@ -17,6 +17,7 @@ namespace TYPO3\CMS\Core\LinkHandling;
 
 use TYPO3\CMS\Core\SingletonInterface;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
+use TYPO3\CMS\Core\Utility\StringUtility;
 
 /**
  * Class LinkService, responsible to find what kind of resource (type) is used
@@ -115,7 +116,7 @@ class LinkService implements SingletonInterface
             if ($fragment) {
                 $result['fragment'] = $fragment;
             }
-        } elseif (strpos($urn, '://') && $this->handlers[self::TYPE_URL]) {
+        } elseif ((strpos($urn, '://') || StringUtility::beginsWith($urn, '//')) && $this->handlers[self::TYPE_URL]) {
             $result = $this->handlers[self::TYPE_URL]->resolveHandlerData(['url' => $urn]);
             $result['type'] = self::TYPE_URL;
         } elseif (stripos($urn, 'mailto:') === 0 && $this->handlers[self::TYPE_EMAIL]) {
diff --git a/typo3/sysext/core/Classes/LinkHandling/UrlLinkHandler.php b/typo3/sysext/core/Classes/LinkHandling/UrlLinkHandler.php
index f8008fcbdfcb5826b111015f4d8814de6226c1ce..803f442e4298111bc98f65a970110ce02a955d41 100644
--- a/typo3/sysext/core/Classes/LinkHandling/UrlLinkHandler.php
+++ b/typo3/sysext/core/Classes/LinkHandling/UrlLinkHandler.php
@@ -14,6 +14,8 @@ namespace TYPO3\CMS\Core\LinkHandling;
  * The TYPO3 project - inspiring people to share!
  */
 
+use TYPO3\CMS\Core\Utility\StringUtility;
+
 /**
  * Resolves URLs (simple, no magic needed)
  */
@@ -51,6 +53,9 @@ class UrlLinkHandler implements LinkHandlingInterface
     protected function addHttpSchemeAsFallback(string $url): string
     {
         if (!empty($url)) {
+            if (StringUtility::beginsWith($url, '//')) {
+                return $url;
+            }
             $scheme = parse_url($url, PHP_URL_SCHEME);
             if (empty($scheme)) {
                 $url = 'http://' . $url;