--- src/lib/VSDContentCollector.cpp
+++ src/lib/VSDContentCollector.cpp
@@ -3220,7 +3220,7 @@
     }
     if (U_SUCCESS(status) && conv)
     {
-      const char *src = (const char *)&characters[0];
+      const char *src = (const char *)characters.data();
       const char *srcLimit = (const char *)src + characters.size();
       while (src < srcLimit)
       {
@@ -3285,6 +3285,7 @@
   _handleLevelChange(level);
   librevenge::RVNGString text;
   std::vector<unsigned char> tmpData(layerMem.m_data.size());
+  if (!layerMem.m_data.empty())
   memcpy(&tmpData[0], layerMem.m_data.getDataBuffer(), layerMem.m_data.size());
   appendCharacters(text, tmpData, layerMem.m_format);