diff --git a/src/fonts.js b/src/fonts.js
index e86be2d20b481..22d2a1cd95db0 100644
--- a/src/fonts.js
+++ b/src/fonts.js
@@ -3870,6 +3870,9 @@ var Font = (function FontClosure() {
         }
       }
 
+      // The following steps modify the original font data, making copy
+      font = new Stream(new Uint8Array(font.getBytes()));
+
       // Check that required tables are present
       var requiredTables = ['OS/2', 'cmap', 'head', 'hhea',
                              'hmtx', 'maxp', 'name', 'post'];
diff --git a/test/pdfs/issue3263.pdf.link b/test/pdfs/issue3263.pdf.link
new file mode 100644
index 0000000000000..9cbad4238f294
--- /dev/null
+++ b/test/pdfs/issue3263.pdf.link
@@ -0,0 +1 @@
+http://visionmedia.dev.cervantesvirtual.com/web/220816.pdf
diff --git a/test/test_manifest.json b/test/test_manifest.json
index a0ab828e8ef98..1f0e5f8794869 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -1113,6 +1113,15 @@
       "rounds": 1,
       "type": "eq"
     },
+    {  "id": "issue3263",
+      "file": "pdfs/issue3263.pdf",
+      "md5": "cee1cf0bd7ce6681cdb97c8e42697d81",
+      "rounds": 1,
+      "link": true,
+      "firstPage": 18,
+      "lastPage": 19,
+      "type": "eq"
+    },
     {  "id": "issue2761",
       "file": "pdfs/issue2761.pdf",
       "md5": "35df0b8cff4afec0c08f08c6a5bc9857",