What is CVE-2021-22903?

CVE-2021-22903 is a medium-severity vulnerability in Rubyonrails Rails, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2021-06-11.

How severe is CVE-2021-22903?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Open Redirect in Rubyonrails Rails

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`.

Vulnerability class: Open Redirect

EPSS: 0.012 (65.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Rubyonrails Rails — versions 6.1.0
N/a Https://github.com/rails/rails — versions Fixed in 6.1.3.2

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

support@hackerone.com (Permissions Required, Third Party Advisory, x_refsource_MISC)
support@hackerone.com (Patch, x_refsource_MISC, Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2021-22903?: CVE-2021-22903 is a medium-severity vulnerability in Rubyonrails Rails, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2021-06-11.
How severe is CVE-2021-22903?: Medium severity. CVSS v3 base score is 6.1 out of 10.