diff --git a/upnp/src/api/upnpapi.c b/upnp/src/api/upnpapi.c
index aa40f6a..55693a4 100644
--- a/upnp/src/api/upnpapi.c
+++ b/upnp/src/api/upnpapi.c
@@ -3878,7 +3878,7 @@ int UpnpAddVirtualDir(const char *newDirName)
 
     if( *newDirName != '/' ) {
         dirName[0] = '/';
-        strncpy( dirName + 1, newDirName, sizeof( dirName ) - 1 );
+        strncpy( dirName + 1, newDirName, sizeof( dirName ) - 2 );
     } else {
         strncpy( dirName, newDirName, sizeof( dirName ) - 1 );
     }