1 files changed, 2 insertions, 0 deletions
diff --git a/Libraries/LibJS/Heap/HeapBlock.h b/Libraries/LibJS/Heap/HeapBlock.h
index 6269ebd45d..3de49c5e28 100644
--- a/Libraries/LibJS/Heap/HeapBlock.h
+++ b/Libraries/LibJS/Heap/HeapBlock.h
@@ -64,6 +64,8 @@ public:
         if (pointer < reinterpret_cast<FlatPtr>(m_storage))
             return nullptr;
         size_t cell_index = (pointer - reinterpret_cast<FlatPtr>(m_storage)) / m_cell_size;
+        if (cell_index >= cell_count())
+            return nullptr;
         return cell(cell_index);
     }