Session replay not working with cookieless_mode on_reject and recordCrossOriginIframes is not showin

[cjoecker]

Bug description

Session replays with recorded on iframes are not being recorded if the page embedded as an iframe has cookieless_mode: "on_reject",

How to reproduce

1. Create a React appliacation and add Posthog
2. Create another React appliacation and add Posthog
3. Embed second application on the first one as iframe
4. Add the following Posthog configuration:

{

				defaults: "2026-01-30",
				capture_exceptions: true,
				cookieless_mode: "on_reject",
				session_recording: {
					maskAllInputs: true,
					maskTextSelector: "*",
					recordCrossOriginIframes: true,
				},
}

Related sub-libraries

• All of them
• posthog-js (web)
• posthog-js-lite (web lite)
• posthog-node
• posthog-react-native
• @posthog/react
• @posthog/ai
• @posthog/nextjs-config
• @posthog/nuxt
• @posthog/rollup-plugin
• @posthog/webpack-plugin

Additional context

Thank you for your bug report – we love squashing them!