diff --git a/core/src/Support/ChunkFileStore.php b/core/src/Support/ChunkFileStore.php
index d8f3f726dd..6021dff554 100644
--- a/core/src/Support/ChunkFileStore.php
+++ b/core/src/Support/ChunkFileStore.php
@@ -54,7 +54,7 @@ public function __construct(array $formats, string $directory)
     public static function make(): self
     {
         $formats = [];
-        $directory = EVO_BASE_PATH . 'views/chunks/';
+        $directory = self::basePath() . 'views/chunks/';
 
         if (function_exists('config')) {
             try {
@@ -68,6 +68,19 @@ public static function make(): self
         return new self($formats, $directory);
     }
 
+    /**
+     * The installation root, with a fallback for processes that run without the
+     * bootstrap constants (the cache refresh worker, tests).
+     *
+     * @since 3.5.8
+     */
+    protected static function basePath(): string
+    {
+        $base = defined('EVO_BASE_PATH') ? (string) EVO_BASE_PATH : dirname(__DIR__, 3) . '/';
+
+        return rtrim(str_replace(chr(92), '/', $base), '/') . '/';
+    }
+
     /**
      * @return array<string, string>
      */
@@ -416,8 +429,10 @@ public function ensureDirectory(): bool
             return false;
         }
 
+        // both dialects: a bare 2.2 directive is a 500 on Apache 2.4 without mod_access_compat
         foreach ([
-            '.htaccess' => "order deny,allow\ndeny from all\n",
+            '.htaccess' => "<IfModule mod_authz_core.c>\n    Require all denied\n</IfModule>\n"
+                . "<IfModule !mod_authz_core.c>\n    Order deny,allow\n    Deny from all\n</IfModule>\n",
             'index.html' => "<h2>Unauthorized access</h2>\nYou're not allowed to access file folder",
         ] as $guard => $body) {
             if (!file_exists($this->directory . '/' . $guard)) {
@@ -431,7 +446,7 @@ public function ensureDirectory(): bool
     /** Relative to the installation: an absolute server path is nobody's business. */
     public function displayDirectory(): string
     {
-        $base = rtrim(str_replace(chr(92), '/', EVO_BASE_PATH), '/') . '/';
+        $base = self::basePath();
         $directory = $this->directory . '/';
 
         return strpos($directory, $base) === 0 ? substr($directory, strlen($base)) : $directory;
diff --git a/core/tests/Unit/Manager/ChunkFileStoreGuardsTest.php b/core/tests/Unit/Manager/ChunkFileStoreGuardsTest.php
new file mode 100644
index 0000000000..2377aa0888
--- /dev/null
+++ b/core/tests/Unit/Manager/ChunkFileStoreGuardsTest.php
@@ -0,0 +1,40 @@
+<?php
+
+use EvolutionCMS\Support\ChunkFileStore;
+
+/**
+ * The chunk directory is guarded by an .htaccess the store writes itself, and the
+ * store is also built by processes that never ran the bootstrap - the cache refresh
+ * worker among them - so neither may depend on Apache 2.2 nor on EVO_BASE_PATH.
+ */
+
+it('writes the directory guard in both the 2.2 and the 2.4 dialect', function () {
+    $dir = sys_get_temp_dir() . '/evo_chunk_guard_' . uniqid();
+    $store = new ChunkFileStore(['html' => 'HTML'], $dir);
+
+    expect($store->ensureDirectory())->toBeTrue();
+
+    $htaccess = (string) file_get_contents($dir . '/.htaccess');
+    expect($htaccess)
+        ->toContain('<IfModule mod_authz_core.c>')
+        ->toContain('Require all denied')
+        ->toContain('<IfModule !mod_authz_core.c>')
+        ->and(preg_match('/^\s*(Order|Deny from)\b/mi', preg_replace('/<IfModule !mod_authz_core\.c>.*?<\/IfModule>/s', '', $htaccess)))
+        ->toBe(0)
+        ->and($htaccess)->toBe((string) file_get_contents(dirname(__DIR__, 4) . '/views/chunks/.htaccess'));
+
+    unlink($dir . '/.htaccess');
+    unlink($dir . '/index.html');
+    rmdir($dir);
+});
+
+it('resolves the installation root without the bootstrap constants', function () {
+    // A separate PHP process: constants defined by other tests must not leak in.
+    $probe = tempnam(sys_get_temp_dir(), 'evo_chunk_probe_');
+    file_put_contents($probe, '<?php require ' . var_export(dirname(__DIR__, 3) . '/vendor/autoload.php', true) . ';'
+        . 'echo defined("EVO_BASE_PATH") ? "defined" : \EvolutionCMS\Support\ChunkFileStore::make()->displayDirectory();');
+    $out = trim((string) shell_exec(escapeshellarg(PHP_BINARY) . ' ' . escapeshellarg($probe) . ' 2>&1'));
+    unlink($probe);
+
+    expect($out)->toBe('views/chunks/');
+});
diff --git a/views/chunks/.htaccess b/views/chunks/.htaccess
index ff2beb844b..fb1de45bdb 100644
--- a/views/chunks/.htaccess
+++ b/views/chunks/.htaccess
@@ -1,2 +1,7 @@
-order deny,allow
-deny from all
+<IfModule mod_authz_core.c>
+    Require all denied
+</IfModule>
+<IfModule !mod_authz_core.c>
+    Order deny,allow
+    Deny from all
+</IfModule>