{"api_version":"1","generated_at":"2026-04-23T01:32:16+00:00","cve":"CVE-2021-22903","urls":{"html":"https://cve.report/CVE-2021-22903","api":"https://cve.report/api/cve/CVE-2021-22903.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2021-22903","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-22903"},"summary":{"title":"CVE-2021-22903","description":"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. 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This causes, for example, `config.hosts << \"sub.example.com\"` to permit a request with a Host header value of `sub-example.com`."}]}},"nvd":{"publishedDate":"2021-06-11 16:15:00","lastModifiedDate":"2021-10-21 14:32:00","problem_types":["CWE-601"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"CHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE","baseScore":6.1,"baseSeverity":"MEDIUM"},"exploitabilityScore":2.8,"impactScore":2.7},"baseMetricV2":{"cvssV2":{"version":"2.0","vectorString":"AV:N/AC:M/Au:N/C:P/I:P/A:N","accessVector":"NETWORK","accessComplexity":"MEDIUM","authentication":"NONE","confidentialityImpact":"PARTIAL","integrityImpact":"PARTIAL","availabilityImpact":"NONE","baseScore":5.8},"severity":"MEDIUM","exploitabilityScore":8.6,"impactScore":4.9,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":true}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.1","versionEndExcluding":"6.1.3.2","cpe_name":[]},{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:rubyonrails:rails:6.1.0:rc2:*:*:*:*:*:*","cpe_name":[]}]}]}},"legacy_mitre":{"record":{"CveYear":"2021","CveId":"22903","Ordinal":"197636","Title":"CVE-2021-22903","CVE":"CVE-2021-22903","Year":"2021"},"notes":[{"CveYear":"2021","CveId":"22903","Ordinal":"1","NoteData":"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 << \"sub.example.com\"` to permit a request with a Host header value of `sub-example.com`.","Type":"Description","Title":null},{"CveYear":"2021","CveId":"22903","Ordinal":"2","NoteData":"2021-06-11","Type":"Other","Title":"Published"},{"CveYear":"2021","CveId":"22903","Ordinal":"3","NoteData":"2021-06-11","Type":"Other","Title":"Modified"}]}}}