1 files changed, 5 insertions, 0 deletions
diff --git a/nbd/server.c b/nbd/server.c
index 41388f5fe9..b0ca9d9771 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1072,6 +1072,11 @@ static ssize_t nbd_co_receive_request(NBDRequest *req,
         rc = command == NBD_CMD_WRITE ? -ENOSPC : -EINVAL;
         goto out;
     }
+    if (request->type & ~NBD_CMD_MASK_COMMAND & ~NBD_CMD_FLAG_FUA) {
+        LOG("unsupported flags (got 0x%x)",
+            request->type & ~NBD_CMD_MASK_COMMAND);
+        return -EINVAL;
+    }
 
     rc = 0;