CVE-2021-22881

mediumpriority · attend · 55EPSS 0.873 · 100 %ileEUUS

grimoire priorityP1 · Urgent

Exploitable?

—

no known exploitation

Likely / severe?

87.3% (100th) EPSS

CVSS 5.8 · medium

Is it mine?

6 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-26

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.

cvss

Technical severity, 0–10. One row per scoring source.

6.1

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.05.8mediumAV:N/AC:M/Au:N/C:P/I:P/A:Nprimary · NVD / NIST USexploitability 8.6 · impact 4.9

v3.16.1mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 2.7

v3.16.1mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:Nsecondary · OSV

v3.16.1mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:Hsecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-601USprimaryCWE-601US

affected products (6)

Products and version ranges known to be affected.

n/a https://github.com/rails/rails≤ Fixed in 6.1.2.1, 6.0.3.5enisa_euvdEU
fedoraproject fedora= 33nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
rubyonrails rails6.0.0 → 6.0.3.5nvdUScpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*
rubyonrails rails6.1.0 → 6.1.2.1nvdUScpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*
RubyGems actionpack6.0.0 → 6.0.3.5osvUSpkg:gem/actionpack
RubyGems actionpack6.1.0 → 6.1.2.1osvUSpkg:gem/actionpack

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-8877-prq4-9xfwActionpack Open Redirect Vulnerability 2021-03-02ghsa · osvUS
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.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2021-02-11modified 2026-06-17

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references (23)

External citations — patches, advisories, analysis.

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