MEDIUM

CVE-2021-22881

CVSS v3

6.1

MEDIUM

EPSS Score

87.3 %

exploit probability, as of 2026-10-19

CISA KEV

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

actionpackRubyGemsfrom 6.1.0 · fixed in 6.1.2.1

Vendor advisories

CVE-2021-22881 Red Hat Product Security2 known affected
rubygem-actionpack: open redirect vulnerability may lead to confidentiality and integrity compromise
cfme-gemset as a component of CloudForms Management Engine 5 · cfme-gemset.src as a component of CloudForms Management Engine 5

Full record on NVD

Description

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.

Technical details

Published: 2021-02-11

Frequently asked questions

What is CVE-2021-22881?

Is CVE-2021-22881 actively exploited?

Active exploitation of CVE-2021-22881 has not been confirmed. Its EPSS score was 87.3% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-22881?

CVE-2021-22881 has a CVSS v3 base score of 6.1 (MEDIUM severity).

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