{"id":"CVE-2021-22881","aliases":["GHSA-8877-prq4-9xfw"],"url":"https://o3.security/vulnerability/CVE-2021-22881","summary":"Actionpack Open Redirect Vulnerability ","details":"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.","published":"2021-02-11T18:15:17.460Z","modified":"2026-09-09T03:30:23.996442455Z","cvss":{"score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"RubyGems","name":"actionpack","fixedVersion":"6.0.3.5"},{"ecosystem":"RubyGems","name":"actionpack","fixedVersion":"6.1.2.1"}],"fix":{"url":"https://github.com/rails/rails/commit/b5de7b3a4787d8a55aaad39f477c16e3af65e444","label":"rails/rails@b5de7b3"},"references":[{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XQ3NS4IBYE2I3MVMGAHFZBZBIZGHXHT3/"},{"type":"ADVISORY","url":"http://www.openwall.com/lists/oss-security/2021/05/05/2"},{"type":"ADVISORY","url":"http://www.openwall.com/lists/oss-security/2021/08/20/1"},{"type":"FIX","url":"http://www.openwall.com/lists/oss-security/2021/12/14/5"},{"type":"FIX","url":"https://benjamin-bouchet.com/cve-2021-22881-faille-de-securite-dans-le-middleware-hostauthorization/"},{"type":"FIX","url":"https://discuss.rubyonrails.org/t/cve-2021-22881-possible-open-redirect-in-host-authorization-middleware/77130"},{"type":"FIX","url":"https://hackerone.com/reports/1047447"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-22881"},{"type":"WEB","url":"https://github.com/rails/rails/commit/b5de7b3a4787d8a55aaad39f477c16e3af65e444"},{"type":"WEB","url":"https://benjamin-bouchet.com/cve-2021-22881-faille-de-securite-dans-le-middleware-hostauthorization"},{"type":"WEB","url":"https://github.com/rails/rails"},{"type":"WEB","url":"https://github.com/rails/rails/blob/v6.1.2.1/actionpack/CHANGELOG.md"},{"type":"WEB","url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2021-22881.yml"},{"type":"WEB","url":"https://groups.google.com/g/rubyonrails-security/c/zN_3qA26l6E"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XQ3NS4IBYE2I3MVMGAHFZBZBIZGHXHT3"},{"type":"WEB","url":"https://rubygems.org/gems/actionpack"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-09T03:30:23.996442455Z"}}