diff --git a/src/core/execute.c b/src/core/execute.c
index 8e70ecab82..7963582ea2 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -2663,6 +2663,7 @@ static int load_credential(
         assert(id);
         assert(path);
         assert(unit);
+        assert(read_dfd >= 0 || read_dfd == AT_FDCWD);
         assert(write_dfd >= 0);
         assert(left);
 
@@ -2889,7 +2890,7 @@ static int acquire_credentials(
                                         lc->path,
                                         lc->encrypted,
                                         unit,
-                                        -1,
+                                        AT_FDCWD,
                                         dfd,
                                         uid,
                                         ownership_ok,