Nextcloud server is a self hosted personal cloud system. Under some circumstance it was possible to bypass the second factor of 2FA after successfully providing the user credentials. It is recommended that the Nextcloud Server is upgraded to 26.0.13, 27.1.8 or 28.0.4 and Nextcloud Enterprise Server is upgraded to 21.0.9.17, 22.2.10.22, 23.0.12.17, 24.0.12.13, 25.0.13.8, 26.0.13, 27.1.8 or 28.0.4.
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.