diff --git a/mozilla/layout/tables/crashtests/347506-1.xhtml b/mozilla/layout/tables/crashtests/347506-1.xhtml
new file mode 100644
index 00000000000..4119389a56d
--- /dev/null
+++ b/mozilla/layout/tables/crashtests/347506-1.xhtml
@@ -0,0 +1,23 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+
+<body>
+
+<div><math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
+
+  <mtable>
+    <mtr>
+       <mtd><mi>x</mi></mtd>
+       <mtd rowspan="4" columnspan="4"><mi>y</mi></mtd>
+    </mtr>
+    <mtr>
+       <mtd rowspan="0" columnspan="0"><mi>z</mi></mtd>
+       <mtd><mi>w</mi></mtd>
+    </mtr>
+  </mtable>
+
+
+</math></div>
+
+</body>
+
+</html>
\ No newline at end of file
diff --git a/mozilla/layout/tables/crashtests/347506-2.xhtml b/mozilla/layout/tables/crashtests/347506-2.xhtml
new file mode 100644
index 00000000000..a6b49febbc0
--- /dev/null
+++ b/mozilla/layout/tables/crashtests/347506-2.xhtml
@@ -0,0 +1,14 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+<body>
+ <table>
+   <tr>
+      <td>x</td>
+      <td rowspan="4" colspan="4">y</td>
+   </tr>
+   <tr>
+      <td rowspan="0" colspan="0">z</td>
+      <td>w</td>
+   </tr>
+ </table> 
+</body>
+</html>
\ No newline at end of file
diff --git a/mozilla/layout/tables/crashtests/crashtests.list b/mozilla/layout/tables/crashtests/crashtests.list
index 05f08ca01e7..9f5303af5c6 100644
--- a/mozilla/layout/tables/crashtests/crashtests.list
+++ b/mozilla/layout/tables/crashtests/crashtests.list
@@ -8,6 +8,8 @@ load 331690-1.html
 load 339315-1.html
 load 341227-1.xhtml
 load 343588-1.xhtml
+load 347506-1.xhtml
+load 347506-2.xhtml
 load 347725-1.xhtml
 load 350524-1.xhtml
 load 351328-1.xhtml
