diff --git a/utils.cpp b/utils.cpp
index 575d328..5329657 100644
--- a/utils.cpp
+++ b/utils.cpp
@@ -541,7 +541,8 @@ std::string formatString(const std::string str, ...)
     vsnprintf(buf, 512, str.c_str(), valist);
     va_end(valist);
 
-    std::string result(buf, 512);
+    size_t len = strlen(buf);
+    std::string result(buf, len);
 
     return result;
 }