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Vulnerability details: VCID-fdqs-v9b2-53gu
Vulnerability ID VCID-fdqs-v9b2-53gu
Aliases CVE-2021-44528
GHSA-qphc-hf5q-v8fc
Summary actionpack Open Redirect in Host Authorization Middleware Specially crafted "X-Forwarded-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. For example, configuration files that look like this: ``` config.hosts << '.EXAMPLE.com' ``` When an allowed host contains a leading dot, a specially crafted Host header can be used to redirect to a malicious website. This vulnerability is similar to CVE-2021-22881 and CVE-2021-22942. Releases -------- The fixed releases are available at the normal locations. Patches ------- To aid users who aren't able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset. * 6-0-host-authorzation-open-redirect.patch - Patch for 6.0 series * 6-1-host-authorzation-open-redirect.patch - Patch for 6.1 series * 7-0-host-authorzation-open-redirect.patch - Patch for 7.0 series Please note that only the 6.1.Z, 6.0.Z, and 5.2.Z series are supported at present. Users of earlier unsupported releases are advised to upgrade as soon as possible as we cannot guarantee the continued availability of security fixes for unsupported releases.
Status Published
Exploitability None
Weighted Severity None
Risk None
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-601 URL Redirection to Untrusted Site ('Open Redirect')
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3 5.4 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-44528.json
epss 0.28611 https://api.first.org/data/v1/epss?cve=CVE-2021-44528
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-qphc-hf5q-v8fc
cvssv3.1 6.1 https://github.com/rails/rails
generic_textual MODERATE https://github.com/rails/rails
cvssv3.1 6.1 https://github.com/rails/rails/blob/v6.1.4.2/actionpack/CHANGELOG.md#rails-6142-december-14-2021
generic_textual MODERATE https://github.com/rails/rails/blob/v6.1.4.2/actionpack/CHANGELOG.md#rails-6142-december-14-2021
cvssv3.1 6.1 https://github.com/rails/rails/commit/0fccfb9a3097a9c4260c791f1a40b128517e7815
generic_textual MODERATE https://github.com/rails/rails/commit/0fccfb9a3097a9c4260c791f1a40b128517e7815
cvssv3.1 6.1 https://github.com/rails/rails/commit/aecba3c301b80e9d5a63c30ea1b287bceaf2c107
generic_textual MODERATE https://github.com/rails/rails/commit/aecba3c301b80e9d5a63c30ea1b287bceaf2c107
cvssv3.1 6.1 https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2021-44528.yml
generic_textual MODERATE https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2021-44528.yml
cvssv3 6.1 https://groups.google.com/g/ruby-security-ann/c/vG9gz3nk1pM/m/7-NU4MNrDAAJ
cvssv3.1 6.1 https://groups.google.com/g/ruby-security-ann/c/vG9gz3nk1pM/m/7-NU4MNrDAAJ
generic_textual MODERATE https://groups.google.com/g/ruby-security-ann/c/vG9gz3nk1pM/m/7-NU4MNrDAAJ
cvssv3.1 6.1 https://groups.google.com/g/ruby-security-ann/c/vG9gz3nk1pM/m/7-NU4MNrDAAJ?utm_medium=email&utm_source=footer
generic_textual MODERATE https://groups.google.com/g/ruby-security-ann/c/vG9gz3nk1pM/m/7-NU4MNrDAAJ?utm_medium=email&utm_source=footer
cvssv3.1 6.1 https://nvd.nist.gov/vuln/detail/CVE-2021-44528
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2021-44528
cvssv3.1 6.1 https://security.netapp.com/advisory/ntap-20240208-0003
generic_textual MODERATE https://security.netapp.com/advisory/ntap-20240208-0003
cvssv3.1 6.1 https://www.debian.org/security/2023/dsa-5372
generic_textual MODERATE https://www.debian.org/security/2023/dsa-5372
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-44528.json
https://api.first.org/data/v1/epss?cve=CVE-2021-44528
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-22942
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-44528
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-21831
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-22577
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-23633
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27777
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-22792
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-22794
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-22795
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-22796
https://github.com/rails/rails
https://github.com/rails/rails/blob/v6.1.4.2/actionpack/CHANGELOG.md#rails-6142-december-14-2021
https://github.com/rails/rails/commit/0fccfb9a3097a9c4260c791f1a40b128517e7815
https://github.com/rails/rails/commit/aecba3c301b80e9d5a63c30ea1b287bceaf2c107
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2021-44528.yml
https://groups.google.com/g/ruby-security-ann/c/vG9gz3nk1pM/m/7-NU4MNrDAAJ
https://groups.google.com/g/ruby-security-ann/c/vG9gz3nk1pM/m/7-NU4MNrDAAJ?utm_medium=email&utm_source=footer
https://nvd.nist.gov/vuln/detail/CVE-2021-44528
https://security.netapp.com/advisory/ntap-20240208-0003
https://security.netapp.com/advisory/ntap-20240208-0003/
https://www.debian.org/security/2023/dsa-5372
1001817 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1001817
2034266 https://bugzilla.redhat.com/show_bug.cgi?id=2034266
GHSA-qphc-hf5q-v8fc https://github.com/advisories/GHSA-qphc-hf5q-v8fc
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-44528.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/rails/rails
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/rails/rails/blob/v6.1.4.2/actionpack/CHANGELOG.md#rails-6142-december-14-2021
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/rails/rails/commit/0fccfb9a3097a9c4260c791f1a40b128517e7815
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/rails/rails/commit/aecba3c301b80e9d5a63c30ea1b287bceaf2c107
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2021-44528.yml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://groups.google.com/g/ruby-security-ann/c/vG9gz3nk1pM/m/7-NU4MNrDAAJ
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://groups.google.com/g/ruby-security-ann/c/vG9gz3nk1pM/m/7-NU4MNrDAAJ?utm_medium=email&utm_source=footer
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-44528
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://security.netapp.com/advisory/ntap-20240208-0003
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

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none

low

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://www.debian.org/security/2023/dsa-5372
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

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Exploit Prediction Scoring System (EPSS)
Percentile 0.96613
EPSS Score 0.28611
Published At May 29, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-05-29T09:13:22.156853+00:00 GithubOSV Importer Import https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/12/GHSA-qphc-hf5q-v8fc/GHSA-qphc-hf5q-v8fc.json 38.6.0