diff --git src/java/org/apache/nutch/crawl/DbUpdateMapper.java src/java/org/apache/nutch/crawl/DbUpdateMapper.java
index 6bab0d7..19e8b41 100644
--- src/java/org/apache/nutch/crawl/DbUpdateMapper.java
+++ src/java/org/apache/nutch/crawl/DbUpdateMapper.java
@@ -17,6 +17,7 @@
 package org.apache.nutch.crawl;
 
 import java.io.IOException;
+import java.net.MalformedURLException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
@@ -87,7 +88,13 @@ GoraMapper<String, WebPage, UrlWithScore, NutchWritable> {
     context.write(urlWithScore, nutchWritable);
 
     for (ScoreDatum scoreDatum : scoreData) {
-      String reversedOut = TableUtil.reverseUrl(scoreDatum.getUrl());
+      String reversedOut;
+      try {
+        reversedOut = TableUtil.reverseUrl(scoreDatum.getUrl());
+      } catch (MalformedURLException e) {
+        LOG.warn("Malformed outlink URL in DbUpdate: {}", scoreDatum.getUrl());
+        continue;
+      }
       scoreDatum.setUrl(url);
       urlWithScore.setUrl(reversedOut);
       urlWithScore.setScore(scoreDatum.getScore());