diff --git a/client/cmddata.c b/client/cmddata.c
index a9f58b962..65fd0d829 100644
--- a/client/cmddata.c
+++ b/client/cmddata.c
@@ -1786,7 +1786,7 @@ int Cmdbin2hex(const char *Cmd) {
 	//Number of digits supplied as argument
 	size_t length = en - bg + 1;
 	size_t bytelen = (length+7) / 8;
-	uint8_t* arr = (uint8_t *) malloc(bytelen);
+	uint8_t* arr = (uint8_t *) calloc(bytelen, sizeof(uint8_t));
 	memset(arr, 0, bytelen);
 	BitstreamOut bout = { arr, 0, 0 };
 
diff --git a/client/cmdhfepa.c b/client/cmdhfepa.c
index b681810ed..dd110c9c0 100644
--- a/client/cmdhfepa.c
+++ b/client/cmdhfepa.c
@@ -43,7 +43,7 @@ int CmdHFEPACollectPACENonces(const char *Cmd)
 			PrintAndLogEx(FAILED, "Error in step %d, Return code: %d",resp.arg[0],(int)resp.arg[1]);
 		} else {
 			size_t nonce_length = resp.arg[1];
-			char *nonce = (char *) malloc(2 * nonce_length + 1);
+			char *nonce = (char *) calloc(2 * nonce_length + 1, sizeof(uint8_t));
 			for(int j = 0; j < nonce_length; j++) {
 				sprintf(nonce + (2 * j), "%02X", resp.d.asBytes[j]);
 			}
diff --git a/client/cmdhficlass.c b/client/cmdhficlass.c
index f0bfa18a0..9427acf50 100644
--- a/client/cmdhficlass.c
+++ b/client/cmdhficlass.c
@@ -404,7 +404,7 @@ int CmdHFiClassSim(const char *Cmd) {
 				break;
 			
 			size_t datalen = NUM_CSNS * 24;
-			void* dump = malloc(datalen);
+			void* dump = calloc(datalen, sizeof(uint8_t));
 			if ( !dump ) {
 				PrintAndLogEx(WARNING, "Failed to allocate memory");
 				return 2;
@@ -456,7 +456,7 @@ int CmdHFiClassSim(const char *Cmd) {
 				break;
 			
 			size_t datalen = NUM_CSNS * 24;
-			void* dump = malloc(datalen);
+			void* dump = calloc(datalen, sizeof(uint8_t));
 			if ( !dump ) {
 				PrintAndLogEx(WARNING, "Failed to allocate memory");
 				return 2;