Misskey is an open source, federated social media platform. Starting in version 12.109.0 and prior to version 2025.2.0-alpha.0, a login token named `token` is stored in a cookie for authentication purposes in Bull Dashboard, but this remains undeleted even after logout is performed. The primary affected users will be users who have logged into Misskey using a public PC or someone else's device, but it's possible that users who have logged out of Misskey before lending their PC to someone else could also be affected. Version 2025.2.0-alpha.0 contains a fix for this issue.
According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization."