diff --git a/registry/source/reflwrit.cxx b/registry/source/reflwrit.cxx
index 854a4e0d865c..62245f6f38be 100644
--- a/registry/source/reflwrit.cxx
+++ b/registry/source/reflwrit.cxx
@@ -62,6 +62,8 @@ sal_uInt32 readString(const sal_uInt8* buffer, sal_Unicode* v, sal_uInt32 maxSiz
         len = maxSize / 2;
     }
 
+    assert(len > 0 && "maxSize has to be >= 2");
+
     for (i = 0; i < len; i++)
     {
         sal_uInt16 aChar;