diff --git a/lib/private/legacy/OC_Util.php b/lib/private/legacy/OC_Util.php
index 35c81dd34e6..94fcb900898 100644
--- a/lib/private/legacy/OC_Util.php
+++ b/lib/private/legacy/OC_Util.php
@@ -1245,14 +1245,14 @@ class OC_Util {
 	 * @return bool
 	 */
 	public static function isSetLocaleWorking() {
-		if ('' === basename('§')) {
+		if ('' === escapeshellcmd('§')) {
 			// Borrowed from \Patchwork\Utf8\Bootup::initLocale
 			setlocale(LC_ALL, 'C.UTF-8', 'C');
 			setlocale(LC_CTYPE, 'en_US.UTF-8', 'fr_FR.UTF-8', 'es_ES.UTF-8', 'de_DE.UTF-8', 'ru_RU.UTF-8', 'pt_BR.UTF-8', 'it_IT.UTF-8', 'ja_JP.UTF-8', 'zh_CN.UTF-8', '0');
 		}
 
 		// Check again
-		if ('' === basename('§')) {
+		if ('' === escapeshellcmd('§')) {
 			return false;
 		}
 		return true;
diff --git a/tests/lib/UtilTest.php b/tests/lib/UtilTest.php
index 04d4858fb26..b9c791735bb 100644
--- a/tests/lib/UtilTest.php
+++ b/tests/lib/UtilTest.php
@@ -74,6 +74,14 @@ class UtilTest extends \Test\TestCase {
 		$this->assertEquals("/%C2%A7%23%40test%25%26%5E%C3%A4/-child", $result);
 	}
 
+	public function testIsSetLocaleWorking() {
+		// OC_Util::isSetLocaleWorking() assumes escapeshellcmd('§') returns '' with non-UTF-8 locale.
+		$locale = setlocale(LC_CTYPE, 0);
+		setlocale(LC_CTYPE, 'C');
+		$this->assertEquals('', escapeshellcmd('§'));
+		setlocale(LC_CTYPE, $locale);
+	}
+
 	public function testFileInfoLoaded() {
 		$expected = function_exists('finfo_open');
 		$this->assertEquals($expected, \OC_Util::fileInfoLoaded());