diff --git a/lib/cli/consolecommand.cpp b/lib/cli/consolecommand.cpp
index b54966e..4b0dff0 100644
--- a/lib/cli/consolecommand.cpp
+++ b/lib/cli/consolecommand.cpp
@@ -580,11 +580,11 @@ Dictionary::Ptr ConsoleCommand::SendRequest()
 
 	http::request<http::string_body> request(http::verb::post, std::string(l_Url->Format(false)), 10);
 
-	request.set(http::field::user_agent, "Icinga/DebugConsole/" + Application::GetAppVersion());
-	request.set(http::field::host, l_Url->GetHost() + ":" + l_Url->GetPort());
+	request.set(http::field::user_agent, std::string{"Icinga/DebugConsole/" + Application::GetAppVersion()});
+	request.set(http::field::host, std::string{l_Url->GetHost() + ":" + l_Url->GetPort()});
 
 	request.set(http::field::accept, "application/json");
-	request.set(http::field::authorization, "Basic " + Base64::Encode(l_Url->GetUsername() + ":" + l_Url->GetPassword()));
+	request.set(http::field::authorization, std::string{"Basic " + Base64::Encode(l_Url->GetUsername() + ":" + l_Url->GetPassword())});
 
 	try {
 		http::write(*l_TlsStream, request);
diff --git a/lib/perfdata/elasticsearchwriter.cpp b/lib/perfdata/elasticsearchwriter.cpp
index 3df9c91..b9b26df 100644
--- a/lib/perfdata/elasticsearchwriter.cpp
+++ b/lib/perfdata/elasticsearchwriter.cpp
@@ -489,8 +489,8 @@ void ElasticsearchWriter::SendRequest(const String& body)
 
 	http::request<http::string_body> request (http::verb::post, std::string(url->Format(true)), 10);
 
-	request.set(http::field::user_agent, "Icinga/" + Application::GetAppVersion());
-	request.set(http::field::host, url->GetHost() + ":" + url->GetPort());
+	request.set(http::field::user_agent, std::string{"Icinga/" + Application::GetAppVersion()});
+	request.set(http::field::host, std::string{url->GetHost() + ":" + url->GetPort()});
 
 	/* Specify required headers by Elasticsearch. */
 	request.set(http::field::accept, "application/json");
@@ -506,7 +506,7 @@ void ElasticsearchWriter::SendRequest(const String& body)
 	String password = GetPassword();
 
 	if (!username.IsEmpty() && !password.IsEmpty())
-		request.set(http::field::authorization, "Basic " + Base64::Encode(username + ":" + password));
+		request.set(http::field::authorization, std::string{"Basic " + Base64::Encode(username + ":" + password)});
 
 	request.body() = body;
 	request.content_length(request.body().size());
diff --git a/lib/perfdata/influxdb2writer.cpp b/lib/perfdata/influxdb2writer.cpp
index 57fc94e..c447f60 100644
--- a/lib/perfdata/influxdb2writer.cpp
+++ b/lib/perfdata/influxdb2writer.cpp
@@ -25,7 +25,7 @@ boost::beast::http::request<boost::beast::http::string_body> Influxdb2Writer::As
 {
 	auto request (AssembleBaseRequest(std::move(body)));
 
-	request.set(boost::beast::http::field::authorization, "Token " + GetAuthToken());
+	request.set(boost::beast::http::field::authorization, std::string{"Token " + GetAuthToken()});
 
 	return std::move(request);
 }
diff --git a/lib/perfdata/influxdbcommonwriter.cpp b/lib/perfdata/influxdbcommonwriter.cpp
index 36d88e2..f898832 100644
--- a/lib/perfdata/influxdbcommonwriter.cpp
+++ b/lib/perfdata/influxdbcommonwriter.cpp
@@ -538,8 +538,8 @@ boost::beast::http::request<boost::beast::http::string_body> InfluxdbCommonWrite
 	auto url (AssembleUrl());
 	http::request<http::string_body> request (http::verb::post, std::string(url->Format(true)), 10);
 
-	request.set(http::field::user_agent, "Icinga/" + Application::GetAppVersion());
-	request.set(http::field::host, url->GetHost() + ":" + url->GetPort());
+	request.set(http::field::user_agent, std::string{"Icinga/" + Application::GetAppVersion()});
+	request.set(http::field::host, std::string{url->GetHost() + ":" + url->GetPort()});
 	request.body() = std::move(body);
 	request.content_length(request.body().size());
 
diff --git a/lib/perfdata/influxdbwriter.cpp b/lib/perfdata/influxdbwriter.cpp
index 30240f7..d7548e2 100644
--- a/lib/perfdata/influxdbwriter.cpp
+++ b/lib/perfdata/influxdbwriter.cpp
@@ -30,7 +30,7 @@ boost::beast::http::request<boost::beast::http::string_body> InfluxdbWriter::Ass
 	if (basicAuth) {
 		request.set(
 			boost::beast::http::field::authorization,
-			"Basic " + Base64::Encode(basicAuth->Get("username") + ":" + basicAuth->Get("password"))
+			std::string{"Basic " + Base64::Encode(basicAuth->Get("username") + ":" + basicAuth->Get("password"))}
 		);
 	}
 
diff --git a/lib/remote/httpserverconnection.cpp b/lib/remote/httpserverconnection.cpp
index cb07557..b6f1969 100644
--- a/lib/remote/httpserverconnection.cpp
+++ b/lib/remote/httpserverconnection.cpp
@@ -511,7 +511,7 @@ void HttpServerConnection::ProcessMessages(boost::asio::yield_context yc)
 			parser.header_limit(1024 * 1024);
 			parser.body_limit(-1);
 
-			response.set(http::field::server, l_ServerHeader);
+			response.set(http::field::server, std::string{l_ServerHeader});
 
 			if (!EnsureValidHeaders(*m_Stream, buf, parser, response, m_ShuttingDown, yc)) {
 				break;
diff --git a/plugins/check_nscp_api.cpp b/plugins/check_nscp_api.cpp
index 3f6843e..2eae6d2 100644
--- a/plugins/check_nscp_api.cpp
+++ b/plugins/check_nscp_api.cpp
@@ -365,11 +365,11 @@ static Dictionary::Ptr FetchData(const String& host, const String& port, const S
 
 	http::request<http::string_body> request (http::verb::get, std::string(url->Format(true)), 10);
 
-	request.set(http::field::user_agent, "Icinga/check_nscp_api/" + String(VERSION));
-	request.set(http::field::host, host + ":" + port);
+	request.set(http::field::user_agent, std::string{"Icinga/check_nscp_api/" + String(VERSION)});
+	request.set(http::field::host, std::string{host + ":" + port});
 
 	request.set(http::field::accept, "application/json");
-	request.set("password", password);
+	request.set("password", std::string{password});
 
 	if (l_Debug) {
 		std::cout << "Sending request to " << url->Format(false, false) << "'.\n";