diff --git a/core/functions/session_proxy.php b/core/functions/session_proxy.php
index 150cbe448e..0be92f67e3 100644
--- a/core/functions/session_proxy.php
+++ b/core/functions/session_proxy.php
@@ -270,6 +270,11 @@ private static function migrateLegacySessionIfNeeded($store): void
      */
     private static function readLegacySessionPayload(string $sessionId): ?string
     {
+        // The cookie becomes part of a file name; Windows resolves "sess_\..\" even without a sess_ folder.
+        if (preg_match('/^[A-Za-z0-9,-]{1,256}$/', $sessionId) !== 1) {
+            return null;
+        }
+
         $savePath = session_save_path();
         if (!is_string($savePath) || $savePath === '') {
             $savePath = sys_get_temp_dir();
@@ -282,7 +287,7 @@ private static function readLegacySessionPayload(string $sessionId): ?string
         }
 
         $file = rtrim($path, "/\\") . DIRECTORY_SEPARATOR . 'sess_' . $sessionId;
-        if (!is_readable($file)) {
+        if (!is_file($file) || !is_readable($file)) {
             return null;
         }
 
diff --git a/core/src/Services/Store/PackageInstallFlowService.php b/core/src/Services/Store/PackageInstallFlowService.php
index d10c67c79b..f0d23bf3cf 100644
--- a/core/src/Services/Store/PackageInstallFlowService.php
+++ b/core/src/Services/Store/PackageInstallFlowService.php
@@ -239,7 +239,7 @@ private function buildDependencyErrorHtml(array $get): string
 <meta http-equiv="Content-Type" content="text/html; charset="utf-8" />
 <link rel="stylesheet" href="' . EVO_SITE_URL . 'assets/modules/store/installer/style.css" type="text/css" media="screen" /></head>
 <body' . $bodyClass . '><div id="contentarea"><div class="container_12"><br>';
-        $html .= '<h2>Error installation</h2><br><br><p>Before install ' . htmlspecialchars((string) ($get['name'] ?? '')) . '<br> Please install this packages: <br>' . implode('<br>', $arrDependencies) . '</p>';
+        $html .= '<h2>Error installation</h2><br><br><p>Before install ' . htmlspecialchars((string) ($get['name'] ?? '')) . '<br> Please install this packages: <br>' . implode('<br>', array_map('htmlspecialchars', $arrDependencies)) . '</p>';
         $html .= "</div><!-- // content --></div><!-- // contentarea --><br /></body></html>";
 
         return $html;
diff --git a/core/tests/Mocks/legacy_session_read_worker.php b/core/tests/Mocks/legacy_session_read_worker.php
new file mode 100644
index 0000000000..f46a1ce70f
--- /dev/null
+++ b/core/tests/Mocks/legacy_session_read_worker.php
@@ -0,0 +1,9 @@
+<?php
+// Reads the legacy session payload for an id from a save path in a fresh process
+// (session_save_path() refuses changes once output was sent). argv: <save path> <hex id>
+[, $savePath, $hexId] = $argv;
+require_once dirname(__DIR__, 2) . '/functions/session_proxy.php';
+
+session_save_path($savePath);
+$method = new ReflectionMethod(EvoSessionProxy::class, 'readLegacySessionPayload');
+echo json_encode($method->invoke(null, hex2bin($hexId)));
diff --git a/core/tests/Mocks/store_dependency_error_worker.php b/core/tests/Mocks/store_dependency_error_worker.php
new file mode 100644
index 0000000000..0a0f97034b
--- /dev/null
+++ b/core/tests/Mocks/store_dependency_error_worker.php
@@ -0,0 +1,24 @@
+<?php
+// Renders the Store "install these packages first" page for argv[1] with no installed elements,
+// so every requested dependency is reported missing. Prints the HTML.
+namespace EvolutionCMS\Models {
+    class StoreWorkerEmptyQuery
+    {
+        public function whereIn($key, $values) { return $this; }
+        public function pluck($key) { return []; }
+    }
+    class SiteSnippet { public static function query() { return new StoreWorkerEmptyQuery(); } }
+    class SitePlugin extends SiteSnippet {}
+    class SiteModule extends SiteSnippet {}
+}
+
+namespace {
+    define('EVO_SITE_URL', 'https://example.invalid/');
+    function evo() { return (object) ['config' => ['manager_theme_mode' => 0]]; }
+
+    require dirname(__DIR__, 2) . '/src/Services/Store/PackageInstallFlowService.php';
+
+    $class = new ReflectionClass(\EvolutionCMS\Services\Store\PackageInstallFlowService::class);
+    $method = $class->getMethod('buildDependencyErrorHtml');
+    echo $method->invoke($class->newInstanceWithoutConstructor(), ['dependencies' => $argv[1], 'name' => 'pkg']);
+}
diff --git a/core/tests/Unit/Security/LegacySessionIdValidationTest.php b/core/tests/Unit/Security/LegacySessionIdValidationTest.php
new file mode 100644
index 0000000000..af9ad1c8f6
--- /dev/null
+++ b/core/tests/Unit/Security/LegacySessionIdValidationTest.php
@@ -0,0 +1,44 @@
+<?php
+
+/*
+| The legacy session cookie is appended to "sess_" to find the old session file. PHP collapses
+| "sess_/../" without the folder existing, so an unchecked cookie could read any file and import
+| it into the visitor's session.
+*/
+
+function legacySessionRead(string $savePath, string $sessionId): ?string
+{
+    // Hex keeps a null byte intact on the command line.
+    $out = evoRunPhp(dirname(__DIR__, 2) . '/Mocks/legacy_session_read_worker.php', [$savePath, bin2hex($sessionId)]);
+
+    return json_decode($out, true, flags: JSON_THROW_ON_ERROR);
+}
+
+beforeEach(function () {
+    $this->root = sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'evo-legacy-session-' . bin2hex(random_bytes(4));
+    $this->store = $this->root . DIRECTORY_SEPARATOR . 'store';
+    mkdir($this->store, 0777, true);
+    file_put_contents($this->root . DIRECTORY_SEPARATOR . 'planted.txt', 'mgrValidated|b:1;');
+    file_put_contents($this->store . DIRECTORY_SEPARATOR . 'sess_abc123,DEF-456', 'legacy|s:2:"ok";');
+});
+
+afterEach(function () {
+    @unlink($this->root . DIRECTORY_SEPARATOR . 'planted.txt');
+    @unlink($this->store . DIRECTORY_SEPARATOR . 'sess_abc123,DEF-456');
+    @rmdir($this->store);
+    @rmdir($this->root);
+});
+
+it('reads a legacy session file named by a well-formed id', function () {
+    expect(legacySessionRead($this->store, 'abc123,DEF-456'))->toBe('legacy|s:2:"ok";');
+});
+
+it('refuses ids that would leave the session directory', function (string $id) {
+    expect(legacySessionRead($this->store, $id))->toBeNull();
+})->with([
+    'slash traversal' => ['/../../planted.txt'],
+    'backslash traversal' => ['\\..\\..\\planted.txt'],
+    'dot segment' => ['..'],
+    'null byte' => ["abc\0"],
+    'too long' => [str_repeat('a', 257)],
+]);
diff --git a/core/tests/Unit/Security/ManagerReflectedXssTest.php b/core/tests/Unit/Security/ManagerReflectedXssTest.php
index fdef55a81b..b9f26288c3 100644
--- a/core/tests/Unit/Security/ManagerReflectedXssTest.php
+++ b/core/tests/Unit/Security/ManagerReflectedXssTest.php
@@ -323,3 +323,15 @@ function paginateLinks(string $extargv): array
         ->and(html_entity_decode(strip_tags($html)))->toBe('Summer sale & more')
         ->not->toContain('onerror');
 });
+
+it('escapes the document fields restored from a posted form', function () {
+    // A template switch or a failed save re-renders the form from $_POST, not from the saved document.
+    $source = managerSource('manager/actions/mutate_content.dynamic.php');
+
+    expect($source)
+        ->toContain("value=\"<?= e(stripslashes(get_by_key(\$content, 'alias', '', 'is_scalar'))) ?>\"")
+        ->toContain("value=\"<?= (int) (\$content['menuindex'] ?? 0) ?>\"")
+        ->toContain("name=\"content_dispo\" value=\"<?= (int) (\$content['content_dispo'] ?? 0) ?>\"")
+        ->not->toContain(": \$content['parent']) ?>")
+        ->and(substr_count($source, ": (int) (\$content['parent'] ?? 0)) ?>"))->toBe(2);
+});
diff --git a/core/tests/Unit/Security/SafeHtmlTest.php b/core/tests/Unit/Security/SafeHtmlTest.php
index 2d31666bb8..2fbe1d94e7 100644
--- a/core/tests/Unit/Security/SafeHtmlTest.php
+++ b/core/tests/Unit/Security/SafeHtmlTest.php
@@ -156,13 +156,18 @@
     expect($out)->toBe('<div class="x">text</div>');
 });
 
-test('executable and resource loading elements are removed with their content', function () {
-    foreach (['script', 'style', 'iframe', 'object', 'embed', 'form', 'svg'] as $tag) {
-        $out = (string) sanitize_rich_html('<p>before</p><' . $tag . '>payload</' . $tag . '><p>after</p>');
+test('executable and resource loading elements are removed with their content', function (string $tag) {
+    $out = (string) sanitize_rich_html('<p>before</p><' . $tag . '>payload</' . $tag . '><p>after</p>');
 
-        expect($out)->toBe('<p>before</p><p>after</p>');
-    }
-});
+    expect($out)->toBe('<p>before</p><p>after</p>');
+})->with(['script', 'style', 'iframe', 'object', 'form', 'svg']);
+
+test('void resource loading elements are removed while adjacent text survives', function (string $tag) {
+    // Void elements have no children; self-closing syntax also keeps older libxml parsers consistent.
+    $out = (string) sanitize_rich_html('<p>before</p><' . $tag . ' src="https://example.test/resource" />text<p>after</p>');
+
+    expect($out)->toBe('<p>before</p>text<p>after</p>');
+})->with(['embed', 'img', 'input', 'source', 'track']);
 
 test('an unknown element is unwrapped so its text stays visible', function () {
     expect((string) sanitize_rich_html('<marquee>still readable</marquee>'))
diff --git a/core/tests/Unit/Security/StoreDependencyErrorEscapingTest.php b/core/tests/Unit/Security/StoreDependencyErrorEscapingTest.php
new file mode 100644
index 0000000000..0d8d80d254
--- /dev/null
+++ b/core/tests/Unit/Security/StoreDependencyErrorEscapingTest.php
@@ -0,0 +1,10 @@
+<?php
+
+// The missing dependency names come from the request (?dependencies=a,b) and are listed back on the page.
+it('escapes the missing dependency names it lists', function () {
+    $html = evoRunPhp(dirname(__DIR__, 2) . '/Mocks/store_dependency_error_worker.php', ['<img src=x onerror=alert(1)>,DocLister']);
+
+    expect($html)
+        ->toContain('&lt;img src=x onerror=alert(1)&gt;<br>DocLister')
+        ->not->toContain('<img src=x');
+});
diff --git a/manager/actions/mutate_content.dynamic.php b/manager/actions/mutate_content.dynamic.php
index 6e58db9b07..2068398179 100644
--- a/manager/actions/mutate_content.dynamic.php
+++ b/manager/actions/mutate_content.dynamic.php
@@ -776,7 +776,7 @@ function evoRenderTvImageCheck(a) {
                                         <i class="<?= $_style["icon_question_circle"] ?>" data-tooltip="<?=ManagerTheme::getLexicon('resource_alias_help');?>"></i>
                                     </td>
                                     <td>
-                                        <input name="alias" type="text" maxlength="100" value="<?= stripslashes(get_by_key($content, 'alias', '', 'is_scalar')) ?>" class="inputBox" onchange="documentDirty=true;" />
+                                        <input name="alias" type="text" maxlength="100" value="<?= e(stripslashes(get_by_key($content, 'alias', '', 'is_scalar'))) ?>" class="inputBox" onchange="documentDirty=true;" />
                                     </td>
                                 </tr>
                                 <tr>
@@ -875,7 +875,7 @@ function evoRenderTvImageCheck(a) {
                                         <i class="<?= $_style["icon_question_circle"] ?>" data-tooltip="<?=ManagerTheme::getLexicon('resource_opt_menu_index_help');?>"></i>
                                     </td>
                                     <td>
-                                        <input name="menuindex" type="text" maxlength="6" value="<?= $content['menuindex'] ?>" class="inputBox" onchange="documentDirty=true;" />
+                                        <input name="menuindex" type="text" maxlength="6" value="<?= (int) ($content['menuindex'] ?? 0) ?>" class="inputBox" onchange="documentDirty=true;" />
                                         <a href="javascript:;" class="btn btn-secondary" onclick="var elm = document.mutate.menuindex;var v=parseInt(elm.value+'')-1;elm.value=v>0? v:0;elm.focus();documentDirty=true;return false;"><i class="<?= $_style['icon_angle_left'] ?>"></i></a>
                                         <a href="javascript:;" class="btn btn-secondary" onclick="var elm = document.mutate.menuindex;var v=parseInt(elm.value+'')+1;elm.value=v>0? v:0;elm.focus();documentDirty=true;return false;"><i class="<?= $_style['icon_angle_right'] ?>"></i></a>
                                     </td>
@@ -928,8 +928,8 @@ function evoRenderTvImageCheck(a) {
                                         }
                                         ?>
                                         <i id="plock" class="<?= $_style["icon_folder"] ?>" onclick="enableParentSelection(!allowParentSelection);"></i>
-                                        <b><span id="parentName"><?= (isset($_REQUEST['pid']) ? entities($_REQUEST['pid']) : $content['parent']) ?> (<?= entities($parentname) ?>)</span></b>
-                                        <input type="hidden" name="parent" value="<?= (isset($_REQUEST['pid']) ? entities($_REQUEST['pid']) : $content['parent']) ?>" onchange="documentDirty=true;" />
+                                        <b><span id="parentName"><?= (isset($_REQUEST['pid']) ? entities($_REQUEST['pid']) : (int) ($content['parent'] ?? 0)) ?> (<?= entities($parentname) ?>)</span></b>
+                                        <input type="hidden" name="parent" value="<?= (isset($_REQUEST['pid']) ? entities($_REQUEST['pid']) : (int) ($content['parent'] ?? 0)) ?>" onchange="documentDirty=true;" />
                                     </td>
                                 </tr>
                                 <tr></tr>
@@ -1411,7 +1411,7 @@ function evoRenderTvImageCheck(a) {
                                         ?>
                                         <input type="hidden" name="contentType" value="<?= e(isset($content['contentType']) ? $content['contentType'] : "text/html") ?>" />
                                         <input type="hidden" name="type" value="document" />
-                                        <input type="hidden" name="content_dispo" value="<?= (isset($content['content_dispo']) ? $content['content_dispo'] : '0') ?>" />
+                                        <input type="hidden" name="content_dispo" value="<?= (int) ($content['content_dispo'] ?? 0) ?>" />
                                         <?php
                                     } else {
                                         // non-admin managers creating or editing a reference (weblink) resource
diff --git a/manager/media/script/tests/tab-changed-mark.test.js b/manager/media/script/tests/tab-changed-mark.test.js
new file mode 100644
index 0000000000..ef796e8ffc
--- /dev/null
+++ b/manager/media/script/tests/tab-changed-mark.test.js
@@ -0,0 +1,80 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+const helper = require('../document-save-helper');
+
+// "Save and continue" saves over XHR and keeps the editor open, so the tab frame is not reloaded
+// and its onload never clears the "changed" mark; the editor announces the save instead.
+const root = path.join(__dirname, '..', '..', '..', '..');
+const evoSource = fs.readFileSync(path.join(root, 'manager', 'media', 'style', 'default', 'js', 'evo.js'), 'utf8');
+const editorSource = fs.readFileSync(path.join(root, 'manager', 'actions', 'mutate_content.dynamic.php'), 'utf8');
+
+function loadWatchChanges() {
+    const match = evoSource.match(/watchChanges: (function \(tabWindow\) \{[\s\S]*?\n {16}\}),\n/);
+    assert.ok(match, 'tab.watchChanges is defined');
+    return new Function('return (' + match[1] + ');')();
+}
+
+function tab() {
+    const classes = new Set();
+    return {
+        watchChanges: loadWatchChanges(),
+        tab: { classList: { add: (c) => classes.add(c), remove: (c) => classes.delete(c), contains: (c) => classes.has(c) } },
+        classes,
+    };
+}
+
+function frame() {
+    const doc = new EventTarget();
+    const live = { click: new Set(), keyup: new Set() };
+    const add = doc.addEventListener.bind(doc);
+    const remove = doc.removeEventListener.bind(doc);
+    doc.addEventListener = (type, fn, o) => { live[type].add(fn); add(type, fn, o); };
+    doc.removeEventListener = (type, fn, o) => { live[type].delete(fn); remove(type, fn, o); };
+    const listeners = () => ({ click: live.click.size, keyup: live.keyup.size });
+    return { win: { document: doc, documentDirty: false }, listeners };
+}
+
+test('the tab is marked changed only once the editor is dirty', () => {
+    const t = tab();
+    const { win, listeners } = frame();
+    t.watchChanges(win);
+
+    win.document.dispatchEvent(new Event('click'));
+    assert.equal(t.classes.has('changed'), false);
+
+    win.documentDirty = true;
+    win.document.dispatchEvent(new Event('keyup'));
+    assert.equal(t.classes.has('changed'), true);
+    assert.deepEqual(listeners(), { click: 0, keyup: 0 });
+});
+
+test('watching again after a save does not stack listeners and marks the next edit', () => {
+    const t = tab();
+    const { win, listeners } = frame();
+    t.watchChanges(win);
+    t.watchChanges(win);
+    assert.deepEqual(listeners(), { click: 1, keyup: 1 });
+
+    win.documentDirty = true;
+    win.document.dispatchEvent(new Event('click'));
+    assert.equal(t.classes.has('changed'), true);
+
+    // what the evo:saved handler does after a successful save
+    win.documentDirty = false;
+    t.tab.classList.remove('changed');
+    t.watchChanges(win);
+    assert.deepEqual(listeners(), { click: 1, keyup: 1 });
+
+    win.documentDirty = true;
+    win.document.dispatchEvent(new Event('keyup'));
+    assert.equal(t.classes.has('changed'), true);
+});
+
+test('the editor announces a successful in-place save and the tab listens for it', () => {
+    assert.match(editorSource, /ajaxSaveHelper\.applyResult\([^\n]*\);\s*ajaxSaveHelper\.announceSaved\(document\);/);
+    const handler = evoSource.match(/addEventListener\('([^']+)', function \(\) \{\s*if \(!tabWindow\.documentDirty\) \{\s*s\.tab\.classList\.remove\('changed'\);\s*s\.watchChanges\(tabWindow\);/);
+    assert.ok(handler, 'evo.js clears the mark on a save event');
+    assert.equal(handler[1], helper.savedEvent);
+});