diff --git a/host/src/simtrace2-cardem-pcsc.c b/host/src/simtrace2-cardem-pcsc.c
index 3ec75098..8b08f36f 100644
--- a/host/src/simtrace2-cardem-pcsc.c
+++ b/host/src/simtrace2-cardem-pcsc.c
@@ -549,6 +549,7 @@ int main(int argc, char **argv)
 
 	do {
 		struct usb_interface_match _ifm, *ifm = &_ifm;
+		memset(ifm, 0, sizeof(*ifm));
 		ifm->vendor = vendor_id;
 		ifm->product = product_id;
 		ifm->configuration = config_id;
diff --git a/host/src/simtrace2-tool.c b/host/src/simtrace2-tool.c
index d7057967..9c9b5ed6 100644
--- a/host/src/simtrace2-tool.c
+++ b/host/src/simtrace2-tool.c
@@ -303,6 +303,7 @@ int main(int argc, char **argv)
 	do {
 		if (transp->udp_fd < 0) {
 			struct usb_interface_match _ifm, *ifm = &_ifm;
+			memset(ifm, 0, sizeof(*ifm));
 			ifm->vendor = vendor_id;
 			ifm->product = product_id;
 			ifm->configuration = config_id;