diff --git a/src/strategy/Engine.cpp b/src/strategy/Engine.cpp
index 27adcd8b..76350375 100644
--- a/src/strategy/Engine.cpp
+++ b/src/strategy/Engine.cpp
@@ -606,7 +606,7 @@ void Engine::LogAction(char const* format, ...)
 
     va_list ap;
     va_start(ap, format);
-    vsprintf(buf, format, ap);
+    vsnprintf(buf, sizeof(buf), format, ap);
     va_end(ap);
 
     lastAction += "|";