CVE-2021-22942
First published: Fri Aug 20 2021(Updated: )
# Overview There is a possible open redirect vulnerability in the Host Authorization middleware in Action Pack. This vulnerability has been assigned the CVE identifier CVE-2021-22942. Versions Affected: >= 6.0.0. Not affected: < 6.0.0 Fixed Versions: 6.1.4.1, 6.0.4.1 # Impact 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: ```ruby 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, but CVE-2021-22881 did not take in to account domain name case sensitivity. # Releases The fixed releases are available at the normal locations. # Workarounds In the case a patch can’t be applied, the following monkey patch can be used in an initializer: ```ruby module ActionDispatch class HostAuthorization HOSTNAME = /[a-z0-9.-]+|\[[a-f0-9]*:[a-f0-9.:]+\]/i VALID_ORIGIN_HOST = /\A(#{HOSTNAME})(?::\d+)?\z/ VALID_FORWARDED_HOST = /(?:\A|,[ ]?)(#{HOSTNAME})(?::\d+)?\z/ private def authorized?(request) origin_host = request.get_header("HTTP_HOST")&.slice(VALID_ORIGIN_HOST, 1) || "" forwarded_host = request.x_forwarded_host&.slice(VALID_FORWARDED_HOST, 1) || "" @permissions.allows?(origin_host) && (forwarded_host.blank? || @permissions.allows?(forwarded_host)) end end end ```
Credit: support@hackerone.com support@hackerone.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| debian/rails | <=2:6.1.4+dfsg-4<=2:6.0.3.7+dfsg-2 | |
| debian/rails | 2:5.2.2.1+dfsg-1+deb10u3 2:5.2.2.1+dfsg-1+deb10u5 2:6.0.3.7+dfsg-2+deb11u2 2:6.1.7.3+dfsg-1 2:6.1.7.3+dfsg-2 | |
| Rubyonrails Rails | >=6.0.0<6.0.4.1 | |
| Rubyonrails Rails | >=6.1.0<6.1.4.1 | |
| rubygems/actionpack | >=6.1.0<=6.1.4 | 6.1.4.1 |
| rubygems/actionpack | >=6.0.0<=6.0.4 | 6.0.4.1 |
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Reference Links
- https://security-tracker.debian.org/tracker/CVE-2021-22942
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-22942
- https://www.openwall.com/lists/oss-security/2021/08/20/1
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=992586
- http://www.openwall.com/lists/oss-security/2021/12/14/5
- https://weblog.rubyonrails.org/2021/8/19/Rails-6-0-4-1-and-6-1-4-1-have-been-released/
- https://www.debian.org/security/2023/dsa-5372
- https://security.netapp.com/advisory/ntap-20240202-0005/
- https://nvd.nist.gov/vuln/detail/CVE-2021-22942
- https://access.redhat.com/security/cve/cve-2021-22942
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2021-22942.yml
- https://groups.google.com/g/rubyonrails-security/c/wB5tRn7h36c
- https://rubygems.org/gems/actionpack
- https://github.com/advisories/GHSA-2rqw-v265-jf8c (Advisory)
Frequently Asked Questions
What is CVE-2021-22942?
CVE-2021-22942 is a possible open redirect vulnerability in the Host Authorization middleware in Action Pack >= 6.0.0.
How does CVE-2021-22942 affect users?
CVE-2021-22942 could allow attackers to redirect users to a malicious website.
What is the severity of CVE-2021-22942?
CVE-2021-22942 has a severity rating of 6.1 (high).
How can I fix CVE-2021-22942?
There is no available fix for CVE-2021-22942 at the moment. It is recommended to monitor the official security sources for any updates or patches.
Where can I find more information about CVE-2021-22942?
You can find more information about CVE-2021-22942 at the following references: [link1](https://security-tracker.debian.org/tracker/CVE-2021-22942), [link2](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-22942), [link3](https://www.openwall.com/lists/oss-security/2021/08/20/1)
- collector/debian-bugs
- alias/CVE-2021-22942
- collector/security-tracker-debian
- collector/nvd-index
- agent/type
- agent/first-publish-date
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- agent/remedy
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- source/GitHub
- alias/GHSA-2rqw-v265-jf8c
- agent/severity
- agent/references
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- agent/description
- collector/nvd-cve
- agent/softwarecombine
- agent/event
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- agent/tags
- agent/trending
- package-manager/debian
- vendor/rubyonrails
- canonical/rubyonrails rails
- version/rubyonrails rails/6.0.0
- version/rubyonrails rails/6.1.0
- package-manager/rubygems