Concorde, formerly know as Nexkey, is a fork of the federated microblogging platform Misskey. Prior to version 12.25Q1.1, due to an improper implementation of the logout process, authentication credentials remain in cookies even after a user has explicitly logged out, which may allow an attacker to steal authentication tokens. This could have devastating consequences if a user with admin privileges is (or was) using a shared device. Users who have logged in on a shared device should go to Settings > Security and regenerate their login tokens. Version 12.25Q1.1 fixes the issue. As a workaround, clear cookies and site data in the browser after logging out.

Concorde, formerly know as Nexkey, is a fork of the federated microblogging platform Misskey. Due to a lack of CSRF countermeasures and improper settings of cookies for MediaProxy authentication, there is a vulnerability that allows MediaProxy authentication to be bypassed. In versions prior to 12.25Q1.1, the authentication cookie does not have the SameSite attribute. This allows an attacker to bypass MediaProxy authentication and load any image without restrictions under certain circumstances. In versions prior to 12.24Q2.3, this cookie was also used to authenticate the job queue management page (bull-board), so bull-board authentication is also bypassed. This may enable attacks that have a significant impact on availability and integrity. The affected versions are too old to be covered by this advisory, but the maintainers of Concorde strongly recommend not using older versions. Version 12.25Q1.1 contains a patch. There is no effective workaround other than updating.