diff --git a/src/core/logging.cpp b/src/core/logging.cpp
index 909da031..942d0b05 100644
--- a/src/core/logging.cpp
+++ b/src/core/logging.cpp
@@ -163,6 +163,7 @@ void LogManager::messageHandler(
 	}
 
 	if (display) {
+		QMutexLocker locker(&self->stdoutMutex);
 		LogMessage::formatMessage(
 		    self->stdoutStream,
 		    message,
diff --git a/src/core/logging.hpp b/src/core/logging.hpp
index bf811333..7b6a758a 100644
--- a/src/core/logging.hpp
+++ b/src/core/logging.hpp
@@ -10,6 +10,7 @@
 #include <qlatin1stringview.h>
 #include <qlogging.h>
 #include <qloggingcategory.h>
+#include <qmutex.h>
 #include <qobject.h>
 #include <qtmetamacros.h>
 
@@ -135,6 +136,7 @@ class LogManager: public QObject {
 	QHash<QLatin1StringView, CategoryFilter> allFilters;
 
 	QTextStream stdoutStream;
+	QMutex stdoutMutex;
 	LoggingThreadProxy threadProxy;
 
 	friend void initLogCategoryLevel(const char* name, QtMsgType defaultLevel);