diff --git a/libfreerdp/common/test/TestFuzzCommonAssistanceHexStringToBin.c b/libfreerdp/common/test/TestFuzzCommonAssistanceHexStringToBin.c
index 6a4a7dc63..b0847d87f 100644
--- a/libfreerdp/common/test/TestFuzzCommonAssistanceHexStringToBin.c
+++ b/libfreerdp/common/test/TestFuzzCommonAssistanceHexStringToBin.c
@@ -2,8 +2,15 @@
 
 int LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size)
 {
-	BYTE* pass = freerdp_assistance_hex_string_to_bin((void*)Data, &Size);
+	char* buf = calloc(Size + 1, sizeof(char));
+	if (buf == NULL)
+		return 0;
+	memcpy(buf, Data, Size);
+	buf[Size] = '\0';
+
+	BYTE* pass = freerdp_assistance_hex_string_to_bin((void*)buf, &Size);
 	free(pass);
+	free(buf);
 
 	return 0;
 }