diff --git a/src/util/uuid.c b/src/util/uuid.c
index f18814885e538eeab54e89730bd7d8aa121507ee..9cafc2ada14b582f486f1832e5c9a570e4e0c688 100644
--- a/src/util/uuid.c
+++ b/src/util/uuid.c
@@ -286,7 +286,8 @@ virSetHostUUIDStr(const char *uuid)
         return EEXIST;
 
     if (!uuid) {
-        if (!getDMISystemUUID(dmiuuid, sizeof(dmiuuid))) {
+        memset(dmiuuid, 0, sizeof(dmiuuid));
+        if (!getDMISystemUUID(dmiuuid, sizeof(dmiuuid) - 1)) {
             if (!virUUIDParse(dmiuuid, host_uuid))
                 return 0;
         }