From 751e9707e72a9c803ded6b179e458501c87e2038 Mon Sep 17 00:00:00 2001
From: Oliver Schmidtmer <O.Schmidtmer@elo.com>
Date: Thu, 23 Sep 2021 23:31:03 +0200
Subject: [PATCH] PDFBOX-5283: ignore dublicate object keys when correcting
 xRefs

---
 .../main/java/org/apache/pdfbox/pdfparser/COSParser.java | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/pdfbox/src/main/java/org/apache/pdfbox/pdfparser/COSParser.java b/pdfbox/src/main/java/org/apache/pdfbox/pdfparser/COSParser.java
index 31b9a341bc6..fa3f9414dac 100644
--- a/pdfbox/src/main/java/org/apache/pdfbox/pdfparser/COSParser.java
+++ b/pdfbox/src/main/java/org/apache/pdfbox/pdfparser/COSParser.java
@@ -1320,8 +1320,13 @@ private Map<COSObjectKey, Long> bfSearchForObjects() throws IOException
                             if (lastObjOffset > 0)
                             {
                                 // add the former object ID only if there was a subsequent object ID
-                                bfCOSObjectKeyOffsets.put(
-                                        new COSObjectKey(lastObjectId, lastGenID), lastObjOffset);
+                                COSObjectKey objectKey = new COSObjectKey(lastObjectId, lastGenID);
+                                if(!bfCOSObjectKeyOffsets.containsKey(objectKey)) {
+                                    bfCOSObjectKeyOffsets.put(objectKey, lastObjOffset);
+                                } else {
+                                    LOG.debug("Ignoring duplicate object key (" + objectKey
+                                            + ")");
+                                }
                             }
                             lastObjectId = objectId;
                             lastGenID = genID;