1 files changed, 20 insertions, 11 deletions

diff --git a/lib/docx/numbering-xml.js b/lib/docx/numbering-xml.js
index 544ba52..9c86536 100644
--- a/lib/docx/numbering-xml.js
+++ b/lib/docx/numbering-xml.js
@@ -17,20 +17,29 @@ function Numbering(nums, abstractNums, styles) {
     );
 
     function findLevel(numId, level) {
+        return findLevelWithSeenNumIds(numId, level, {});
+    }
+
+    function findLevelWithSeenNumIds(numId, level, seenNumIds) {
+        if (seenNumIds[numId]) {
+            return null;
+        }
+        seenNumIds[numId] = true;
+
         var num = nums[numId];
-        if (num) {
-            var abstractNum = abstractNums[num.abstractNumId];
-            if (!abstractNum) {
-                return null;
-            } else if (abstractNum.numStyleLink == null) {
-                return abstractNums[num.abstractNumId].levels[level];
-            } else {
-                var style = styles.findNumberingStyleById(abstractNum.numStyleLink);
-                return findLevel(style.numId, level);
-            }
-        } else {
+        if (!num) {
             return null;
         }
+
+        var abstractNum = abstractNums[num.abstractNumId];
+        if (!abstractNum) {
+            return null;
+        } else if (abstractNum.numStyleLink == null) {
+            return abstractNums[num.abstractNumId].levels[level];
+        } else {
+            var style = styles.findNumberingStyleById(abstractNum.numStyleLink);
+            return findLevelWithSeenNumIds(style.numId, level, seenNumIds);
+        }
     }
 
     function findLevelByParagraphStyleId(styleId) {