diff --git a/CHANGELOG.md b/CHANGELOG.md
index c65bf20..0d8f1b6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 * security: Move the graph 'Add to QuickTree' icon's inline `onClick='addQuickTree()'` handler into a delegated jQuery binding in `js/quicktree.js` (via a `quicktreeAddLink` class and `data-` attributes) and 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
 * dev: Replace the translation-template CI check that regenerated locales/po/cacti.pot and compared it with a diff-based gate (tests/bin/check-i18n-pot.php) requiring cacti.pot to be updated only when a pull request adds, removes, or modifies an i18n function call
 * dev: Measure CI coverage with xdebug instead of pcov so the plugin's own sources are instrumented (pcov auto-scopes to the Composer root and skipped cacti/plugins/, leaving the patch-coverage gate with nothing to measure)
+* security: Normalize the requested location before building the breadcrumb URL so a crafted location value is not reflected into the navigation
 * dev: Enforce patch coverage of changed lines in CI and remove the inert COMPOSER_ROOT_VERSION env from the Pest step
 * security: Add a version-safe CSP nonce (`plugin_quicktree_csp_nonce()`) to every inline `<script>` tag so pages stay compatible with Cacti's Content-Security-Policy nonce enforcement, while falling back cleanly on older Cacti releases that lack the `CactiSecureHeaders` class
 - issue: Quicktree continually registers a realm
diff --git a/setup.php b/setup.php
index 9d0049f..71983f3 100644
--- a/setup.php
+++ b/setup.php
@@ -284,10 +284,12 @@ function quicktree_page_head(): void {
  *               added.
  */
 function quicktree_draw_navigation_text($nav): array {
+	include_once(__DIR__ . '/includes/security.php');
+
 	$nav['quicktree.php:'] =  [
 		'title'   => __('QuickTree', 'quicktree'),
 		'mapping' => (get_nfilter_request_var('location') == 'console' ? 'index.php:' : ''),
-		'url'     => 'quicktree.php?location=' . get_nfilter_request_var('location'),
+		'url'     => 'quicktree.php?location=' . quicktree_normalize_location(get_nfilter_request_var('location')),
 		'level'   => '1'
 	];
 
diff --git a/tests/Unit/QuicktreeNavigationTextTest.php b/tests/Unit/QuicktreeNavigationTextTest.php
new file mode 100644
index 0000000..d9f7672
--- /dev/null
+++ b/tests/Unit/QuicktreeNavigationTextTest.php
@@ -0,0 +1,34 @@
+<?php
+/*
+ +-------------------------------------------------------------------------+
+ | Copyright (C) 2004-2026 The Cacti Group                                 |
+ +-------------------------------------------------------------------------+
+ | Cacti: The Complete RRDtool-based Graphing Solution                     |
+ +-------------------------------------------------------------------------+
+*/
+
+/*
+ * The breadcrumb URL is rendered into the page, so the request's location
+ * value must never reach it unnormalized.
+ */
+
+beforeAll(function () {
+	require_once __DIR__ . '/../../setup.php';
+});
+
+afterEach(function () {
+	$GLOBALS['__test_request_vars'] = array();
+});
+
+it('builds the breadcrumb from a normalized location', function ($location, $mapping, $url) {
+	$GLOBALS['__test_request_vars']['location'] = $location;
+
+	$nav = quicktree_draw_navigation_text(array());
+
+	expect($nav['quicktree.php:']['mapping'])->toBe($mapping);
+	expect($nav['quicktree.php:']['url'])->toBe($url);
+})->with([
+	'console'  => ['console', 'index.php:', 'quicktree.php?location=console'],
+	'tab'      => ['tab', '', 'quicktree.php?location=tab'],
+	'hostile'  => ['"><script>alert(1)</script>&action=clear', '', 'quicktree.php?location=tab'],
+]);