diff --git a/phpBB/config/default/container/services_content.yml b/phpBB/config/default/container/services_content.yml
index 8b240067e4..e2d53784c2 100644
--- a/phpBB/config/default/container/services_content.yml
+++ b/phpBB/config/default/container/services_content.yml
@@ -67,6 +67,14 @@ services:
             - '@controller.helper'
             - '@dispatcher'
 
+    posting.lock:
+        class: phpbb\lock\posting
+        shared: false
+        arguments:
+            - '@cache.driver'
+            - '@config'
+            - '@request'
+
     viewonline_helper:
         class: phpbb\viewonline_helper
         arguments:
diff --git a/phpBB/phpbb/lock/posting.php b/phpBB/phpbb/lock/posting.php
new file mode 100644
index 0000000000..d912475890
--- /dev/null
+++ b/phpBB/phpbb/lock/posting.php
@@ -0,0 +1,82 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\lock;
+
+use phpbb\cache\driver\driver_interface as cache_interface;
+use phpbb\config\config;
+use phpbb\request\request_interface;
+
+class posting
+{
+	/** @var cache_interface */
+	private $cache;
+
+	/** @var config */
+	private $config;
+
+	/** @var request_interface */
+	private $request;
+
+	/** @var string */
+	private $lock_name = '';
+
+	/**
+	 * Constructor for posting lock
+	 *
+	 * @param cache_interface $cache
+	 * @param config $config
+	 * @param request_interface $request
+	 */
+	public function __construct(cache_interface $cache, config $config, request_interface $request)
+	{
+		$this->cache = $cache;
+		$this->config = $config;
+		$this->request = $request;
+	}
+
+	/**
+	 * Get lock name
+	 * @return string Lock name
+	 */
+	private function lock_name(): string
+	{
+		if ($this->lock_name)
+		{
+			return $this->lock_name;
+		}
+
+		$creation_time	= abs($this->request->variable('creation_time', 0));
+		$token = $this->request->variable('form_token', '');
+
+		return sha1(((string) $creation_time) . $token) . '_posting_lock';
+	}
+
+	/**
+	 * Acquire lock for current posting form submission
+	 *
+	 * @return bool True if lock could be acquired, false if not
+	 */
+	public function acquire(): bool
+	{
+		// Lock is held for session, cannot acquire it
+		if ($this->cache->_exists($this->lock_name()))
+		{
+			return false;
+		}
+
+		$this->cache->put($this->lock_name(), true, $this->config['flood_interval']);
+
+		return true;
+	}
+}
\ No newline at end of file
diff --git a/phpBB/posting.php b/phpBB/posting.php
index 724d8a8df1..7b3d2243ab 100644
--- a/phpBB/posting.php
+++ b/phpBB/posting.php
@@ -1429,7 +1429,10 @@ if ($submit || $preview || $refresh)
 	// Store message, sync counters
 	if (!count($error) && $submit)
 	{
-		if ($submit)
+		/** @var \phpbb\lock\posting $posting_lock */
+		$posting_lock = $phpbb_container->get('posting.lock');
+
+		if ($posting_lock->acquire())
 		{
 			// Lock/Unlock Topic
 			$change_topic_status = $post_data['topic_status'];
@@ -1620,6 +1623,11 @@ if ($submit || $preview || $refresh)
 
 			redirect($redirect_url);
 		}
+		else
+		{
+			// Posting was already locked before, hence form submission was already attempted once and is now invalid
+			$error[] = $language->lang('FORM_INVALID');
+		}
 	}
 }
 
diff --git a/phpBB/styles/prosilver/template/ajax.js b/phpBB/styles/prosilver/template/ajax.js
index 79187470d8..e01e7eb4d4 100644
--- a/phpBB/styles/prosilver/template/ajax.js
+++ b/phpBB/styles/prosilver/template/ajax.js
@@ -337,6 +337,29 @@ $('[data-ajax]').each(function() {
 	}
 });
 
+// Prevent accidental double submission of form
+$('[data-prevent-flood] input[type=submit]').click(function(event) {
+	const $submitButton = $(this); // Store the button element
+	const $form = $submitButton.closest('form');
+
+	// Always add the disabled class for visual feedback
+	$submitButton.addClass('disabled');
+
+	// Submit form if it hasn't been submitted yet
+	if (!$form.prop('data-form-submitted')) {
+		$form.prop('data-form-submitted', true);
+
+		return;
+	}
+
+	// Prevent default submission for subsequent clicks within 5 seconds
+	event.preventDefault();
+
+	setTimeout(() => {
+		$form.prop('removeProp', 'data-form-submitted');
+		$submitButton.removeClass('disabled'); // Re-enable after 5 seconds
+	}, 5000);
+});
 
 /**
  * This simply appends #preview to the action of the
diff --git a/phpBB/styles/prosilver/template/posting_editor.html b/phpBB/styles/prosilver/template/posting_editor.html
index 12790360d6..d3b2ecd68e 100644
--- a/phpBB/styles/prosilver/template/posting_editor.html
+++ b/phpBB/styles/prosilver/template/posting_editor.html
@@ -100,7 +100,7 @@
 	<!-- IF not S_SHOW_DRAFTS and not $SIG_EDIT eq 1 -->
 	<div class="panel bg2">
 		<div class="inner">
-		<fieldset class="submit-buttons">
+		<fieldset class="submit-buttons" data-prevent-flood>
 			{S_HIDDEN_ADDRESS_FIELD}
 			{S_HIDDEN_FIELDS}
 			<!-- EVENT posting_editor_submit_buttons -->