In the Samly package before 1.4.0 for Elixir, Samly.State.Store.get_assertion/3 can return an expired session, which interferes with access control because Samly.AuthHandler uses a cached session and does not replace it, even after expiry.
https://github.com/handnot2/samly
https://github.com/dropbox/samly/pull/13/commits/812b5c3ad076dc9c9334c1a560c8e6470607d1eb
https://github.com/dropbox/samly/pull/13