diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 60a377c7..e88ddbf6 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -811,6 +811,7 @@ my $net_fmt = {
 	type => 'string',
 	description => $net_fmt_bridge_descr,
 	format_description => 'bridge',
+	pattern => '[-_.\w\d]+',
 	optional => 1,
     },
     queues => {