diff --git a/fs/vfs/fs_open.c b/fs/vfs/fs_open.c
index 08a3f24f64..a66f62e869 100644
--- a/fs/vfs/fs_open.c
+++ b/fs/vfs/fs_open.c
@@ -260,6 +260,7 @@ int open(const char *path, int oflags, ...)
        */
 
       fd = (int)OPEN_GETFD(ret);
+      DEBUGASSERT((unsigned)fd < (CONFIG_NFILE_DESCRIPTORS + CONFIG_NSOCKET_DESCRIPTORS));
     }
 #endif