Add field validation for recaptcha action names

src/Resources/contao/classes/RecaptchaHooks.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Contao;
+
+class RecaptchaHooks
+{
+    public function addRecaptchaActionRegexp($regexpName, $value, Widget $widget)
+    {
+        if ($regexpName !== 'recaptcha') return false;
+
+        if (preg_match('/[^a-zA-Z\/_]/', $value) !== 0) {
+            $widget->addError($GLOBALS['TL_LANG']['ERR']['recaptcha_rgxp']);
+        }
+
+        return true;
+    }
+}

src/Resources/contao/config/config.php

@@ -3,6 +3,7 @@
 use DieSchittigs\RecaptchaBundle\Form\FormRecaptcha;
 
 $GLOBALS['TL_FFL']['captcha'] = FormRecaptcha::class;
+$GLOBALS['TL_HOOKS']['addCustomRegexp'][] = [Contao\RecaptchaHooks::class, 'addRecaptchaActionRegexp'];
 
 array_insert($GLOBALS['TL_CTE']['miscellaneous'], 0, [
     'backgroundrecaptcha' => Contao\ContentBackgroundRecaptcha::class,

src/Resources/contao/dca/tl_content.php

@@ -7,7 +7,7 @@
         'label' => &$GLOBALS['TL_LANG']['tl_content']['recaptcha_action'],
         'exclude' => true,
         'inputType' => 'text',
-        'eval' => ['tl_class' => 'w50', 'required' => true],
+        'eval' => ['tl_class' => 'w50', 'required' => true, 'rgxp' => 'recaptcha'],
         'sql' => 'VARCHAR(120) NOT NULL',
     ],
 ];

src/Resources/contao/dca/tl_form_field.php

@@ -11,7 +11,7 @@
         'label'             => &$GLOBALS['TL_LANG']['tl_form_field']['recaptcha3_action'],
         'inputType'         => 'text',
         'sql'               => "varchar(120) unsigned NOT NULL default ''",
-        'eval'              => ['tl_class' => 'w50']
+        'eval'              => ['tl_class' => 'w50', 'rgxp' => 'recaptcha']
     ],
 ];
 

src/Resources/contao/languages/de/default.php

@@ -1,6 +1,7 @@
 <?php
 
 $GLOBALS['TL_LANG']['ERR']['recaptcha'] = "reCAPTCHA konnte nicht bestätigen, dass Sie kein Roboter sind. Bitte versuchen Sie es noch einmal.";
+$GLOBALS['TL_LANG']['ERR']['recaptcha_rgxp'] = "reCAPTCHA Aktionen können nur die Buchstaben a-z (klein- und großgeschrieben), sowie die Zeichen _ und / enthalten.";
 
 $GLOBALS['TL_LANG']['CTE']['miscellaneous'] = "Verschiedenes";
 $GLOBALS['TL_LANG']['CTE']['backgroundrecaptcha'][0] = "Hintergrund reCAPTCHA v3";

src/Resources/contao/languages/en/default.php

@@ -1,6 +1,7 @@
 <?php
 
 $GLOBALS['TL_LANG']['ERR']['recaptcha'] = "reCAPTCHA could not verify that you're not a robot. Please try again.";
+$GLOBALS['TL_LANG']['ERR']['recaptcha_rgxp'] = "reCAPTCHA actions can only include the letters a-z (lower and upper case) and the symbols _ and /.";
 
 $GLOBALS['TL_LANG']['CTE']['miscellaneous'] = "Miscellaneous";
 $GLOBALS['TL_LANG']['CTE']['backgroundrecaptcha'][0] = "Background reCAPTCHA v3";