CVE-2025-32441 is a medium-severity vulnerability affecting the Rack Ruby web server interface, specifically versions prior to 2.2.14 when using the Rack::Session::Pool middleware. Rack manages web sessions by preparing session data at the start of a request and saving it back after processing. This process is vulnerable to race conditions due to improper synchronization when handling concurrent requests within the same session. An attacker who has obtained a valid session cookie can exploit this flaw by triggering a long-running request concurrent with a legitimate user logging out. Because the session deletion and restoration are not atomic, the attacker can restore a deleted session and maintain unauthorized access even after the user attempts to log out. This vulnerability arises from concurrent execution using shared resources without proper synchronization (CWE-362), leading to potential session fixation or hijacking scenarios. The patch in version 2.2.14 addresses this by ensuring atomic session invalidation. Alternative mitigations include marking sessions as logged out with a flag rather than deleting them outright and verifying this flag on each request, or implementing a custom session store that tracks invalidation timestamps to reject stale session data. The CVSS 3.1 score is 4.2, reflecting low confidentiality and integrity impact with no availability impact, requiring low privileges and no user interaction, but with high attack complexity.

For European organizations, this vulnerability poses a risk primarily to web applications built on Ruby using the Rack framework with the vulnerable session middleware. Exploitation could allow attackers to maintain unauthorized access to user sessions even after logout, potentially leading to data exposure or unauthorized actions under the victim's identity. This undermines user trust and may violate data protection regulations such as the GDPR, especially if personal data is accessed or manipulated. The impact is more pronounced for applications handling sensitive or regulated data, including financial services, healthcare, and government portals. While the vulnerability requires the attacker to have a session cookie (which itself implies some prior compromise or phishing), the ability to extend session validity post-logout increases the window for exploitation. This can facilitate further attacks like privilege escalation or data theft. The medium severity rating suggests moderate risk, but organizations with high-value targets or strict compliance requirements should prioritize remediation.

European organizations should upgrade all Rack installations to version 2.2.14 or later to apply the official patch. Where immediate upgrade is not feasible, implement application-level mitigations: (1) Modify session invalidation logic to mark sessions as logged out using a dedicated flag instead of deleting them, and enforce checks on this flag at every request to prevent reuse of invalidated sessions. (2) Develop or deploy a custom session store that records session invalidation timestamps and rejects session data if the session was invalidated after the request started, preventing race condition exploitation. Additionally, enforce strict session cookie security measures such as HttpOnly and Secure flags, and monitor for unusual session activity patterns. Conduct code reviews and penetration testing focused on session management concurrency issues. Finally, educate developers about race conditions and proper synchronization techniques in web session handling.