diff --git a/build/gen_stub.php b/build/gen_stub.php
index acee1e6ca0981..e5fbe4867525c 100755
--- a/build/gen_stub.php
+++ b/build/gen_stub.php
@@ -6048,9 +6048,10 @@ function installPhpParser(string $version, string $phpParserDir) {
         chdir(__DIR__);
 
         $tarName = "v$version.tar.gz";
-        passthru("wget https://github.com/nikic/PHP-Parser/archive/$tarName", $exit);
+        $downloadUrl = "https://github.com/nikic/PHP-Parser/archive/$tarName";
+        passthru("wget -O $tarName $downloadUrl", $exit);
         if ($exit !== 0) {
-            passthru("curl -LO https://github.com/nikic/PHP-Parser/archive/$tarName", $exit);
+            passthru("curl -LO $downloadUrl", $exit);
         }
         if ($exit !== 0) {
             throw new Exception("Failed to download PHP-Parser tarball");
@@ -6060,6 +6061,7 @@ function installPhpParser(string $version, string $phpParserDir) {
         }
         passthru("tar xvzf $tarName -C PHP-Parser-$version --strip-components 1", $exit);
         if ($exit !== 0) {
+            rmdir($phpParserDir);
             throw new Exception("Failed to extract PHP-Parser tarball");
         }
         unlink(__DIR__ . "/$tarName");
diff --git a/ext/standard/mail.c b/ext/standard/mail.c
index 8c8b4e6717e0b..b631d12e4c7e2 100644
--- a/ext/standard/mail.c
+++ b/ext/standard/mail.c
@@ -218,7 +218,8 @@ PHPAPI zend_string *php_mail_build_headers(HashTable *headers)
 	ZEND_HASH_FOREACH_KEY_VAL(headers, idx, key, val) {
 		if (!key) {
 			zend_type_error("Header name cannot be numeric, " ZEND_LONG_FMT " given", idx);
-			break;
+			smart_str_free(&s);
+			return NULL;
 		}
 		ZVAL_DEREF(val);
 		/* https://tools.ietf.org/html/rfc2822#section-3.6 */
diff --git a/ext/standard/tests/mail/gh20776.phpt b/ext/standard/tests/mail/gh20776.phpt
new file mode 100644
index 0000000000000..aec68c4719202
--- /dev/null
+++ b/ext/standard/tests/mail/gh20776.phpt
@@ -0,0 +1,15 @@
+--TEST--
+GH-20776: mail() memory leak when header array contains numeric keys
+--FILE--
+<?php
+$to = "user@example.com";
+$subject = $message = "";
+
+try {
+    var_dump(mail($to, $subject, $message, ['RandomHeader' => 'Value', 5 => 'invalid key']));
+} catch (Throwable $e) {
+    echo $e::class, ': ', $e->getMessage(), PHP_EOL;
+}
+?>
+--EXPECT--
+TypeError: Header name cannot be numeric, 5 given