diff --git a/src/ripple/shamap/impl/SHAMapTreeNode.cpp b/src/ripple/shamap/impl/SHAMapTreeNode.cpp
index 0222db491c..03ddbc7cdd 100644
--- a/src/ripple/shamap/impl/SHAMapTreeNode.cpp
+++ b/src/ripple/shamap/impl/SHAMapTreeNode.cpp
@@ -475,6 +475,7 @@ SHAMapInnerNodeV2::addRaw(Serializer& s, SHANodeFormat format) const
 {
     if (format == snfPREFIX)
     {
+        assert(depth_ <= 64);
         s.add32 (HashPrefix::innerNodeV2);
 
         for (int i = 0 ; i < 16; ++i)