diff --git a/web/pdf_attachment_viewer.js b/web/pdf_attachment_viewer.js
index 6646830cd94852..079b083ca221f5 100644
--- a/web/pdf_attachment_viewer.js
+++ b/web/pdf_attachment_viewer.js
@@ -172,6 +172,7 @@ class PDFAttachmentViewer extends BaseTreeViewer {
 
       const element = document.createElement("a");
       if (
+        (typeof PDFJSDev === "undefined" || !PDFJSDev.test("MOZCENTRAL")) &&
         PdfFileRegExp.test(filename) &&
         !viewerCompatibilityParams.disableCreateObjectURL
       ) {