diff --git a/src/util/util.c b/src/util/util.c
index 79ca5d3e8a..1b5bc68d68 100644
--- a/src/util/util.c
+++ b/src/util/util.c
@@ -570,8 +570,7 @@ __virExec(const char *const*argv,
             i != null &&
             i != childout &&
             i != childerr &&
-            (!keepfd ||
-             !FD_ISSET(i, keepfd))) {
+            (!keepfd || (i < FD_SETSIZE && !FD_ISSET(i, keepfd)))) {
             tmpfd = i;
             VIR_FORCE_CLOSE(tmpfd);
         }