diff --git a/src/osgPlugins/zip/unzip.cpp b/src/osgPlugins/zip/unzip.cpp
index daec066b0..4caf31da1 100644
--- a/src/osgPlugins/zip/unzip.cpp
+++ b/src/osgPlugins/zip/unzip.cpp
@@ -1810,6 +1810,8 @@ uInt *v)               // working area: values in order of bit length
   int y;                        // number of dummy codes added 
   uInt z;                       // number of entries in current table 
 
+  // provide a default value
+  r.base = 0;
 
   // Generate counts for each bit length 
   p = c;