Session ids could be fixed by an attacker if the site is configured with server-side session storage (CKAN uses cookie-based session storage by default). The attacker would need to either set a cookie on the victim's browser or steal the victim's currently valid session. Session identifiers are now regenerated after each login.

This vulnerability has been fixed in CKAN 2.10.9 and 2.11.4

[https://en.wikipedia.org/wiki/Session fixation](https://en.wikipedia.org/wiki/Session fixation)