rack is vulnerable to information disclosure. The vulnerability exists due to the insecure comparison of session IDs. A remote attacker is able to perform timing attacks by analyzing the response time of the server when performing the comparison of session IDs.
lists.opensuse.org/opensuse-security-announce/2020-02/msg00016.html
www.openwall.com/lists/oss-security/2019/12/18/2
www.openwall.com/lists/oss-security/2019/12/18/3
www.openwall.com/lists/oss-security/2019/12/19/3
www.openwall.com/lists/oss-security/2020/04/08/1
www.openwall.com/lists/oss-security/2020/04/09/2
github.com/rack/rack/commit/7fecaee81f59926b6e1913511c90650e76673b38
github.com/rack/rack/security/advisories/GHSA-hrqr-hxpp-chr3
lists.fedoraproject.org/archives/list/[email protected]/message/HZXMWILCICQLA2BYSP6I2CRMUG53YBLX/