diff --git a/src/libnm-glib-aux/nm-shared-utils.h b/src/libnm-glib-aux/nm-shared-utils.h
index dcf37cd332..bcc2ac3a45 100644
--- a/src/libnm-glib-aux/nm-shared-utils.h
+++ b/src/libnm-glib-aux/nm-shared-utils.h
@@ -2770,7 +2770,7 @@ nm_utils_strdup_reset_take(char **dst, char *src)
     char *old;
 
     nm_assert(dst);
-    nm_assert(src != *dst);
+    nm_assert(!src || src != *dst);
 
     if (nm_streq0(*dst, src)) {
         if (src)