diff --git a/CHANGELOG.md b/CHANGELOG.md
index cce5507..e789d7f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 --- develop ---
 
+* security: Replace the confirmation pages' inline `onClick='cactiReturnTo()'` Cancel buttons with the CSP-safe `cactiReturnTo` class so the pages no longer trip Cacti's Content-Security-Policy script-src-attr directive; see the README for the one-time `applySkin()` snippet needed when running Cacti below 1.2.31 (1.2.31+ binds the class automatically)
 * issue: Fix an uncaught `TypeError` from `html_nav_bar()` (the schedules, devices, webseer and servcheck lists passed the `page`/`rows`/`total_rows` request values as strings, which the typed core signature rejects under `declare(strict_types=1)`); the paging arguments are now cast to `int`
 * refactor: Move schema management into includes/database.php (the thold model) and relocate functions.php into includes/; setup.php delegates via require_once, and plugin_maint_check_upgrade() now refreshes the schema via db_update_table(), re-registers the is_device_in_maintenance hook against includes/functions.php, and updates the full plugin_config row on a version change. Switches every file inclusion from include/include_once to require/require_once
 * dev: Enforce patch coverage of changed lines in CI and remove the inert COMPOSER_ROOT_VERSION env from the Pest step
diff --git a/README.md b/README.md
index 48c4acf..e4a3070 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,20 @@
 The Cacti maint plugin is for the scheduling of maintenance so that Thold /
 Webseer / Other plugins will not alert during that time period.
 
+## Cacti compatibility
+
+If you are running a version of Cacti below 1.2.31, please add the function
+below to the `applySkin()` function in `include/layout.js` to enable the Cancel
+buttons on forms to work:
+
+```js
+$(document).off('click.cactiReturnTo', '.cactiReturnTo')
+    .on('click.cactiReturnTo', '.cactiReturnTo', function(event) {
+        event.preventDefault();
+        cactiReturnTo($(this).attr('data-url'));
+    });
+```
+
 ## Installation
 
 To install the plugin, please refer to the Plugin Installation Documentation
diff --git a/maint.php b/maint.php
index d5a8bf9..be5d723 100644
--- a/maint.php
+++ b/maint.php
@@ -430,7 +430,7 @@ function form_actions(): void {
 					</td>
 				</tr>";
 
-				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget' onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Cancel', 'maint') . "</button>
+				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Cancel', 'maint') . "</button>
 					<button type='submit' class='ui-button ui-corner-all ui-widget ui-state-active' title='" . __esc('Update Maintenance Schedule(s)', 'maint') . "'>" . __esc('Continue', 'maint') . '</button>';
 			} elseif (get_request_var('drp_action') == '2') { // delete
 				print "<tr>
@@ -440,11 +440,11 @@ function form_actions(): void {
 					</td>
 				</tr>";
 
-				$save_html = "<input type='button' value='" . __esc('Cancel', 'maint') . "' onClick='cactiReturnTo(\"maint.php\")'>&nbsp;<input type='submit' value='" . __esc('Continue', 'maint') . "' title='" . __esc('Delete Maintenance Schedule(s)', 'maint') . "'>";
+				$save_html = "<input class='cactiReturnTo' data-url='maint.php' type='button' value='" . __esc('Cancel', 'maint') . "'>&nbsp;<input type='submit' value='" . __esc('Continue', 'maint') . "' title='" . __esc('Delete Maintenance Schedule(s)', 'maint') . "'>";
 			}
 		} else {
 			print "<tr><td><span class='textError'>" . __('You must select at least one Maintenance Schedule.', 'maint') . '</span></td></tr>';
-			$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget' onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Return', 'maint') . '</button';
+			$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Return', 'maint') . '</button>';
 		}
 
 		print "<tr class='saveRow'>
@@ -499,7 +499,7 @@ function form_actions(): void {
 					</td>
 				</tr>";
 
-				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget' onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Cancel', 'maint') . "</button>
+				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Cancel', 'maint') . "</button>
 					<button type='submit' class='ui-button ui-corner-all ui-widget ui-state-active' title='" . __esc('Associate Maintenance Schedule(s)', 'maint') . "'>" . __esc('Continue', 'maint') . '</button>';
 			} elseif (get_request_var('drp_action') == '2') { // disassociate
 				print "<tr>
@@ -509,12 +509,12 @@ function form_actions(): void {
 					</td>
 				</tr>";
 
-				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget' onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Cancel', 'maint') . "</button>
+				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Cancel', 'maint') . "</button>
 					<button type='submit' class='ui-button ui-corner-all ui-widget ui-state-active' title='" . __esc('Disassociate Maintenance Schedule(s)', 'maint') . "'>" . __esc('Continue', 'maint') . '</button>';
 			}
 		} else {
 			print "<tr><td><span class='textError'>" . __('You must select at least one Device.', 'maint') . '</span></td></tr>';
-			$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget' onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Return', 'maint') . '</button>';
+			$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Return', 'maint') . '</button>';
 		}
 
 		print "<tr class='saveRow'>
@@ -569,7 +569,7 @@ function form_actions(): void {
 					</td>
 				</tr>";
 
-				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget' onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Cancel', 'maint') . "</button>
+				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Cancel', 'maint') . "</button>
 					<button type='submit' class='ui-button ui-corner-all ui-widget ui-state-active' title='" . __esc('Associate Maintenance Schedule(s)', 'maint') . "'>" . __esc('Continue', 'maint') . '</button>';
 			} elseif (get_request_var('drp_action') == '2') { // disassociate
 				print "<tr>
@@ -579,12 +579,12 @@ function form_actions(): void {
 					</td>
 				</tr>";
 
-				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget' onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Cancel', 'maint') . "</button>
+				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Cancel', 'maint') . "</button>
 					<button type='submit' class='ui-button ui-corner-all ui-widget ui-state-active' title='" . __esc('Disassociate Maintenance Schedule(s)', 'maint') . "'>" . __esc('Continue', 'maint') . '</button>';
 			}
 		} else {
 			print "<tr><td><span class='textError'>" . __('You must select at least one Webseer.', 'maint') . '</span></td></tr>';
-			$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget'> onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Return', 'maint') . '</button>';
+			$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Return', 'maint') . '</button>';
 		}
 
 		print "<tr class='saveRow'>
@@ -639,7 +639,7 @@ function form_actions(): void {
 					</td>
 				</tr>";
 
-				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget' onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Cancel', 'maint') . "</button>
+				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Cancel', 'maint') . "</button>
 					<button type='submit' class='ui-button ui-corner-all ui-widget ui-state-active' title='" . __esc('Associate Maintenance Schedule(s)', 'maint') . "'>" . __esc('Continue', 'maint') . '</button>';
 			} elseif (get_request_var('drp_action') == '2') { // disassociate
 				print "<tr>
@@ -649,12 +649,12 @@ function form_actions(): void {
 					</td>
 				</tr>";
 
-				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget' onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Cancel', 'maint') . "</button>
+				$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Cancel', 'maint') . "</button>
 					<input type='submit' class='ui-button ui-corner-all ui-widget ui-state-active' title='" . __esc('Disassociate Maintenance Schedule(s)', 'maint') . "'>" . __esc('Continue', 'maint') . '</button>';
 			}
 		} else {
 			print "<tr><td><span class='textError'>" . __('You must select at least one Servcheck test.', 'maint') . '</span></td></tr>';
-			$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget' onClick='cactiReturnTo(\"maint.php\")'>" . __esc('Return', 'maint') . '</button>';
+			$save_html = "<button type='button' class='ui-button ui-corner-all ui-widget cactiReturnTo' data-url='maint.php'>" . __esc('Return', 'maint') . '</button>';
 		}
 
 		print "<tr class='saveRow'>