{"id":"CVE-2021-22903","details":"The actionpack ruby gem before 6.1.3.2 suffers from a possible 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. This is similar to CVE-2021-22881. Strings in config.hosts that do not have a leading dot are converted to regular expressions without proper escaping. This causes, for example, `config.hosts \u003c\u003c \"sub.example.com\"` to permit a request with a Host header value of `sub-example.com`.","aliases":["GHSA-5hq2-xf89-9jxq"],"modified":"2025-11-14T11:15:06.410873Z","published":"2021-06-11T16:15:11.437Z","references":[{"type":"FIX","url":"https://discuss.rubyonrails.org/t/cve-2021-22903-possible-open-redirect-vulnerability-in-action-pack/77867"},{"type":"REPORT","url":"https://hackerone.com/reports/1148025"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/rails/rails","events":[{"introduced":"5f3ff60084ab5d5921ca3499814e4697f8350ee7"},{"fixed":"75ac626c4e21129d8296d4206a1960563cc3d4aa"}]}],"versions":["v6.1.1","v6.1.2","v6.1.2.1","v6.1.3","v6.1.3.1"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2021-22903.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"}]}