The Host Authorization middleware in Action Pack before 6.1.2.1, 6.0.3.5 suffers from an open redirect vulnerability. Specially crafted `Host` headers in combination with certain "allowed host" formats can cause the Host Authorization middleware in Action Pack to redirect users to a malicious website. Impacted applications will have allowed hosts with a leading dot. When an allowed host contains a leading dot, a specially crafted `Host` header can be used to redirect to a malicious website.
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.
| Link | Tags |
|---|---|
| https://hackerone.com/reports/1047447 | patch third party advisory exploit |
| https://discuss.rubyonrails.org/t/cve-2021-22881-possible-open-redirect-in-host-authorization-middleware/77130 | patch vendor advisory mitigation |
| https://benjamin-bouchet.com/cve-2021-22881-faille-de-securite-dans-le-middleware-hostauthorization/ | third party advisory patch |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XQ3NS4IBYE2I3MVMGAHFZBZBIZGHXHT3/ | vendor advisory |
| http://www.openwall.com/lists/oss-security/2021/05/05/2 | mailing list mitigation third party advisory |
| http://www.openwall.com/lists/oss-security/2021/08/20/1 | mailing list mitigation third party advisory |
| http://www.openwall.com/lists/oss-security/2021/12/14/5 | patch mailing list exploit |