--- a/accessible/atk/nsMaiInterfaceTableCell.cpp
+++ b/accessible/atk/nsMaiInterfaceTableCell.cpp
@@ -50,16 +50,19 @@ GetRowSpanCB(AtkTableCell* aCell)
   return 0;
 }
 
 static gboolean
 GetPositionCB(AtkTableCell* aCell, gint* aRow, gint* aCol)
 {
   if (AccessibleWrap* accWrap = GetAccessibleWrap(ATK_OBJECT(aCell))) {
     TableCellAccessible* cell = accWrap->AsTableCell();
+    if (!cell) {
+      return false;
+    }
     *aRow = cell->RowIdx();
     *aCol = cell->ColIdx();
     return true;
   }
 
   if (ProxyAccessible* proxy = GetProxy(ATK_OBJECT(aCell))) {
     uint32_t rowIdx = 0, colIdx = 0;
     proxy->GetPosition(&rowIdx, &colIdx);
@@ -71,16 +74,19 @@ GetPositionCB(AtkTableCell* aCell, gint*
   return false;
 }
 
 static gboolean
 GetColumnRowSpanCB(AtkTableCell* aCell, gint* aCol, gint* aRow,
                    gint* aColExtent, gint* aRowExtent) {
   if (AccessibleWrap* accWrap = GetAccessibleWrap(ATK_OBJECT(aCell))) {
     TableCellAccessible* cellAcc = accWrap->AsTableCell();
+    if (!cellAcc) {
+      return false;
+    }
     *aCol = cellAcc->ColIdx();
     *aRow = cellAcc->RowIdx();
     *aColExtent = cellAcc->ColExtent();
     *aRowExtent = cellAcc->ColExtent();
     return true;
   }
 
   if (ProxyAccessible* proxy = GetProxy(ATK_OBJECT(aCell))) {