VW breaks Home Assistant integration by mandating client assertion on login

Volkswagen has rolled out a change to its identity service that now requires a client assertion during authentication, breaking the popular homeassistant-volkswagencarnet community integration. Users report that logins through Home Assistant fail with a generic ‘authentication not possible’ error, while the official Android app and the vwid.vwgroup.io web portal continue to work normally with the same credentials.

The new requirement effectively locks out third-party clients that cannot produce a signed assertion proving they are an approved VW application. This is a common pattern automakers use to harden their telematics APIs against scraping and unofficial clients, but it also kills legitimate owner-built automation that relies on reverse-engineered auth flows. The GitHub issue thread is filling with affected users across multiple car models and regions, and the maintainers have no immediate workaround since the change is server-side.

For the Home Assistant community this is the latest in a recurring pattern where OEM telematics integrations break whenever the manufacturer tightens OAuth or adds attestation. Owners who paid for We Connect subscriptions to power their dashboards are left waiting on either a project-level credential extraction workaround or a policy reversal from Volkswagen.