diff --git a/poi/src/main/java/org/apache/poi/hssf/record/FeatRecord.java b/poi/src/main/java/org/apache/poi/hssf/record/FeatRecord.java
index a434658ba4..86e2fc8f57 100644
--- a/poi/src/main/java/org/apache/poi/hssf/record/FeatRecord.java
+++ b/poi/src/main/java/org/apache/poi/hssf/record/FeatRecord.java
@@ -132,13 +132,15 @@ public final class FeatRecord extends StandardRecord {
             cellRef.serialize(out);
         }
 
-        sharedFeature.serialize(out);
+        if (sharedFeature != null) {
+            sharedFeature.serialize(out);
+        }
     }
 
     protected int getDataSize() {
         return 12 + 2+1+4+2+4+2+
-            (cellRefs.length * CellRangeAddress.ENCODED_SIZE)
-            +sharedFeature.getDataSize();
+            (cellRefs.length * CellRangeAddress.ENCODED_SIZE) +
+                (sharedFeature == null ? 0 : sharedFeature.getDataSize());
     }
 
     public int getIsf_sharedFeatureType() {
diff --git a/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffViewer.java b/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffViewer.java
index 4655517e08..491d68d159 100644
--- a/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffViewer.java
+++ b/poi/src/test/java/org/apache/poi/hssf/dev/TestBiffViewer.java
@@ -45,6 +45,7 @@ class TestBiffViewer extends BaseTestIteratingXLS {
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5786329142919168.xls", IllegalStateException.class);
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5889658057523200.xls", IndexOutOfBoundsException.class);
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5175219985448960.xls", IndexOutOfBoundsException.class);
+        excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-6137883240824832.xls", IndexOutOfBoundsException.class);
 
         return excludes;
     }
diff --git a/poi/src/test/java/org/apache/poi/hssf/dev/TestRecordLister.java b/poi/src/test/java/org/apache/poi/hssf/dev/TestRecordLister.java
index c04d994a43..7f1c1f4561 100644
--- a/poi/src/test/java/org/apache/poi/hssf/dev/TestRecordLister.java
+++ b/poi/src/test/java/org/apache/poi/hssf/dev/TestRecordLister.java
@@ -48,6 +48,8 @@ class TestRecordLister extends BaseTestIteratingXLS {
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5786329142919168.xls", RecordFormatException.class);
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5889658057523200.xls", IndexOutOfBoundsException.class);
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5175219985448960.xls", RecordFormatException.class);
+        excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-6137883240824832.xls", RecordFormatException.class);
+
         return excludes;
     }
 
diff --git a/test-data/spreadsheet/clusterfuzz-testcase-minimized-POIHSSFFuzzer-6137883240824832.xls b/test-data/spreadsheet/clusterfuzz-testcase-minimized-POIHSSFFuzzer-6137883240824832.xls
new file mode 100644
index 0000000000..a9920e797b
Binary files /dev/null and b/test-data/spreadsheet/clusterfuzz-testcase-minimized-POIHSSFFuzzer-6137883240824832.xls differ
diff --git a/test-data/spreadsheet/stress.xls b/test-data/spreadsheet/stress.xls
index f04e974e02..1e6d98a3a8 100644
Binary files a/test-data/spreadsheet/stress.xls and b/test-data/spreadsheet/stress.xls differ