diff --git a/pkg/fatfs/fatfs_vfs/fatfs_vfs.c b/pkg/fatfs/fatfs_vfs/fatfs_vfs.c
index 97344fd776..e96d09bf6d 100644
--- a/pkg/fatfs/fatfs_vfs/fatfs_vfs.c
+++ b/pkg/fatfs/fatfs_vfs/fatfs_vfs.c
@@ -90,6 +90,9 @@ static int _format(vfs_mount_t *mountp)
 
     /* make sure the volume has been initialized */
     if (_init(mountp)) {
+#if !CONFIG_FATFS_FORMAT_ALLOC_STATIC
+        free(work);
+#endif
         return -EINVAL;
     }