diff --git a/toolkit/components/extensions/Extension.jsm b/toolkit/components/extensions/Extension.jsm
index 7281518..322dc09 100644
--- a/toolkit/components/extensions/Extension.sys.mjs
+++ b/toolkit/components/extensions/Extension.sys.mjs
@@ -3286,6 +3286,14 @@ class Extension extends ExtensionData {
       this.permissions.add(PRIVATE_ALLOWED_PERMISSION);
     }
 
+    // Allow all addons in private mode.
+    lazy.ExtensionPermissions.add(this.id, {
+	   permissions: [PRIVATE_ALLOWED_PERMISSION],
+	   origins: [],
+    });
+    this.permissions.add(PRIVATE_ALLOWED_PERMISSION);
+
+
     // We only want to update the SVG_CONTEXT_PROPERTIES_PERMISSION during
     // install and upgrade/downgrade startups.
     if (INSTALL_AND_UPDATE_STARTUP_REASONS.has(this.startupReason)) {