diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFTable.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFTable.java
index 863a7527d4..4954fe3f60 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFTable.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFTable.java
@@ -114,7 +114,7 @@ public class XSLFTable extends XSLFGraphicFrame implements Iterable<XSLFTableRow
 
     @Override
     public int getNumberOfColumns() {
-        return _table.getTblGrid().sizeOfGridColArray();
+        return _table.getTblGrid() == null ? 0 : _table.getTblGrid().sizeOfGridColArray();
     }
 
     @Override
diff --git a/test-data/slideshow/clusterfuzz-testcase-minimized-POIXSLFFuzzer-6254434927378432.pptx b/test-data/slideshow/clusterfuzz-testcase-minimized-POIXSLFFuzzer-6254434927378432.pptx
new file mode 100644
index 0000000000..4517920eee
Binary files /dev/null and b/test-data/slideshow/clusterfuzz-testcase-minimized-POIXSLFFuzzer-6254434927378432.pptx differ
diff --git a/test-data/spreadsheet/stress.xls b/test-data/spreadsheet/stress.xls
index b4c297fe28..55c4c0d33c 100644
Binary files a/test-data/spreadsheet/stress.xls and b/test-data/spreadsheet/stress.xls differ