diff --git a/wp-admin/includes/class-file-upload-upgrader.php b/wp-admin/includes/class-file-upload-upgrader.php
index e62561518d..1201c6d188 100644
--- a/wp-admin/includes/class-file-upload-upgrader.php
+++ b/wp-admin/includes/class-file-upload-upgrader.php
@@ -70,24 +70,7 @@ class File_Upload_Upgrader {
 			}
 
 			if ( 'pluginzip' === $form || 'themezip' === $form ) {
-				$archive_is_valid = false;
-
-				/** This filter is documented in wp-admin/includes/file.php */
-				if ( class_exists( 'ZipArchive', false ) && apply_filters( 'unzip_file_use_ziparchive', true ) ) {
-					$archive          = new ZipArchive();
-					$archive_is_valid = $archive->open( $file['file'], ZIPARCHIVE::CHECKCONS );
-
-					if ( true === $archive_is_valid ) {
-						$archive->close();
-					}
-				} else {
-					require_once ABSPATH . 'wp-admin/includes/class-pclzip.php';
-
-					$archive          = new PclZip( $file['file'] );
-					$archive_is_valid = is_array( $archive->properties() );
-				}
-
-				if ( true !== $archive_is_valid ) {
+				if ( ! wp_zip_file_is_valid( $file['file'] ) ) {
 					wp_delete_file( $file['file'] );
 					wp_die( __( 'Incompatible Archive.' ) );
 				}
diff --git a/wp-admin/includes/file.php b/wp-admin/includes/file.php
index c3863ba2ea..583256955e 100644
--- a/wp-admin/includes/file.php
+++ b/wp-admin/includes/file.php
@@ -1563,6 +1563,37 @@ function wp_trusted_keys() {
 	return apply_filters( 'wp_trusted_keys', $trusted_keys );
 }
 
+/**
+ * Determines whether the given file is a valid ZIP file.
+ *
+ * This function does not test to ensure that a file exists. Non-existent files
+ * are not valid ZIPs, so those will also return false.
+ *
+ * @since 6.4.4
+ *
+ * @param string $file Full path to the ZIP file.
+ * @return bool Whether the file is a valid ZIP file.
+ */
+function wp_zip_file_is_valid( $file ) {
+	/** This filter is documented in wp-admin/includes/file.php */
+	if ( class_exists( 'ZipArchive', false ) && apply_filters( 'unzip_file_use_ziparchive', true ) ) {
+		$archive          = new ZipArchive();
+		$archive_is_valid = $archive->open( $file, ZipArchive::CHECKCONS );
+		if ( true === $archive_is_valid ) {
+			$archive->close();
+			return true;
+		}
+	}
+
+	// Fall through to PclZip if ZipArchive is not available, or encountered an error opening the file.
+	require_once ABSPATH . 'wp-admin/includes/class-pclzip.php';
+
+	$archive          = new PclZip( $file );
+	$archive_is_valid = is_array( $archive->properties() );
+
+	return $archive_is_valid;
+}
+
 /**
  * Unzips a specified ZIP file to a location on the filesystem via the WordPress
  * Filesystem Abstraction.
diff --git a/wp-includes/version.php b/wp-includes/version.php
index f4f8391a95..5ce28ffa6e 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.5-alpha-57536';
+$wp_version = '6.5-alpha-57537';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.