When using the Rack::Session::Pool
middleware, simultaneous rack requests can restore a deleted rack session, which allows the unauthenticated user to occupy that session.
Rack session middleware prepares the session at the beginning of request, then saves is back to the store with possible changes applied by host rack application. This way the session becomes to be a subject of race conditions in general sense over concurrent rack requests.
When using the Rack::Session::Pool
middleware, and provided the attacker can acquire a session cookie (already a major issue), the session may be restored if the attacker can trigger a long running request (within that same session) adjacent to the user logging out, in order to retain illicit access even after a user has attempted to logout.
rack
, orlogged_out
flag, instead of deleting them, and check this flag on every request to prevent reuse, orAs this code was moved to rack-session
in Rack 3+, see https://github.com/rack/rack-session/security/advisories/GHSA-9j94-67jr-4cqj for the equivalent advisory in rack-session
(affecting Rack 3+ only).
{ "nvd_published_at": "2025-05-07T23:15:53Z", "cwe_ids": [ "CWE-362", "CWE-367", "CWE-613" ], "severity": "MODERATE", "github_reviewed": true, "github_reviewed_at": "2025-05-08T14:45:18Z" }