From c17801b77e27f9889b05339636e5f02835f0e49f Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Fri, 20 Mar 2026 10:37:11 +0100
Subject: [PATCH] Avoid getting null value in RefSet when cloning

---
 src/core/editor/pdf_editor.js            | 12 +++++++-----
 test/pdfs/.gitignore                     |  1 +
 test/pdfs/extractPages_null_in_array.pdf | 21 +++++++++++++++++++++
 test/unit/api_spec.js                    | 16 ++++++++++++++++
 4 files changed, 45 insertions(+), 5 deletions(-)
 create mode 100644 test/pdfs/extractPages_null_in_array.pdf

diff --git a/src/core/editor/pdf_editor.js b/src/core/editor/pdf_editor.js
index 1b64907ef..b4b84b4ae 100644
--- a/src/core/editor/pdf_editor.js
+++ b/src/core/editor/pdf_editor.js
@@ -249,7 +249,8 @@ class PDFEditor {
         obj = obj.slice();
       }
       for (let i = 0, ii = obj.length; i < ii; i++) {
-        const postponedActions = postponedRefCopies.get(obj[i]);
+        const postponedActions =
+          obj[i] instanceof Ref && postponedRefCopies.get(obj[i]);
         if (postponedActions) {
           // The object is a reference that needs to be copied later.
           postponedActions.push(ref => (obj[i] = ref));
@@ -277,7 +278,8 @@ class PDFEditor {
     }
     if (dict) {
       for (const [key, rawObj] of dict.getRawEntries()) {
-        const postponedActions = postponedRefCopies.get(rawObj);
+        const postponedActions =
+          rawObj instanceof Ref && postponedRefCopies.get(rawObj);
         if (postponedActions) {
           // The object is a reference that needs to be copied later.
           postponedActions.push(ref => dict.set(key, ref));
@@ -1083,7 +1085,7 @@ class PDFEditor {
 
       // Fix the ID tree.
       for (const [id, nodeRef] of idTree || []) {
-        const newNodeRef = oldRefMapping.get(nodeRef);
+        const newNodeRef = nodeRef instanceof Ref && oldRefMapping.get(nodeRef);
         const newId = dedupIDs.get(id) || id;
         if (newNodeRef) {
           newIdTree.set(newId, newNodeRef);
@@ -1137,7 +1139,7 @@ class PDFEditor {
       const newDestinations = (documentData.destinations = new Map());
       for (const [key, dest] of Object.entries(destinations)) {
         const pageRef = dest[0];
-        const pageData = pagesMap.get(pageRef);
+        const pageData = pageRef instanceof Ref && pagesMap.get(pageRef);
         if (!pageData) {
           continue;
         }
@@ -1537,7 +1539,7 @@ class PDFEditor {
       }
       const { oldRefMapping } = documentData;
       for (const coRef of co) {
-        const newCoRef = oldRefMapping.get(coRef);
+        const newCoRef = coRef instanceof Ref && oldRefMapping.get(coRef);
         if (newCoRef) {
           calculationOrder.push(newCoRef);
         }
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index 13e26879f..54eecbe68 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -888,3 +888,4 @@
 !outlines_for_editor.pdf
 !mesh_shading_empty.pdf
 !acroform_calculation_order.pdf
+!extractPages_null_in_array.pdf
diff --git a/test/pdfs/extractPages_null_in_array.pdf b/test/pdfs/extractPages_null_in_array.pdf
new file mode 100644
index 000000000..cc62b270e
--- /dev/null
+++ b/test/pdfs/extractPages_null_in_array.pdf
@@ -0,0 +1,21 @@
+%PDF-1.0
+1 0 obj
+<< /Type /Catalog /Pages 2 0 R >>
+endobj
+2 0 obj
+<< /Type /Pages /Kids [3 0 R] /Count 1 >>
+endobj
+3 0 obj
+<< /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] /Resources << /Dummy [null] >> >>
+endobj
+xref
+0 4
+0000000000 65535 f 
+0000000009 00000 n 
+0000000058 00000 n 
+0000000115 00000 n 
+trailer
+<< /Size 4 /Root 1 0 R >>
+startxref
+217
+%%EOF
diff --git a/test/unit/api_spec.js b/test/unit/api_spec.js
index 7ce81129f..0547afef4 100644
--- a/test/unit/api_spec.js
+++ b/test/unit/api_spec.js
@@ -6763,5 +6763,21 @@ small scripts as well as for`);
         await newLoadingTask.destroy();
       });
     });
+
+    describe("extract pages with null values in arrays", function () {
+      it("should not crash when a page resource contains an array with null entries", async function () {
+        const loadingTask = getDocument(
+          buildGetDocumentParams("extractPages_null_in_array.pdf")
+        );
+        const pdfDoc = await loadingTask.promise;
+        const data = await pdfDoc.extractPages([{ document: null }]);
+        await loadingTask.destroy();
+
+        const newLoadingTask = getDocument(data);
+        const newPdfDoc = await newLoadingTask.promise;
+        expect(newPdfDoc.numPages).toEqual(1);
+        await newLoadingTask.destroy();
+      });
+    });
   });
 });