CVE-2021-22903

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`.

• CWE-601
• CWE-601

• https://discuss.rubyonrails.org/t/cve-2021-22903-possible-open-redirect-vulnerability-in-action-pack/77867Mitigation, Patch, Vendor Advisory
• https://hackerone.com/reports/1148025Permissions Required, Third Party Advisory
• https://discuss.rubyonrails.org/t/cve-2021-22903-possible-open-redirect-vulnerability-in-action-pack/77867Mitigation, Patch, Vendor Advisory
• https://hackerone.com/reports/1148025Permissions Required, Third Party Advisory

Published

Jun 11, 2021

Last Modified

Jun 17, 2026

Status

Modified

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