GitHub Advisoryadvisory · RubyGems
GHSA-g8ww-46x2-2p65 Denial of Service in Action Dispatch
HIGH
Official page ↗
- Aliases
- CVE-2021-22902
- Ecosystem
- RubyGems
- Packages
- actionpack
- Severity
- High
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-400
- Reviewed
- 2021-05-05
Affected packages
• RubyGems actionpack: >= 6.0.0, < 6.0.3.7 → fixed in 6.0.3.7
• RubyGems actionpack: >= 6.1.0, < 6.1.3.2 → fixed in 6.1.3.2
Description
Impact
------
There is a possible Denial of Service vulnerability in Action Dispatch. Carefully crafted Accept headers can cause the mime type parser in Action Dispatch to do catastrophic backtracking in the regular expression engine.
Releases
--------
The fixed releases are available at the normal locations.
Workarounds
-----------
The following monkey patch placed in an initializer can be used to work around the issue.
```ruby
module Mime
class Type
MIME_REGEXP = /\A(?:\*\/\*|#{MIME_NAME}\/(?:\*|#{MIME_NAME})(?>\s*#{MIME_PARAMETER}\s*)*)\z/
end
end
```
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-Prevent-catastrophic-backtracking-during-mime-parsin.patch - Patch for 6.0 series
• 6-1-Prevent-catastrophic-backtracking-during-mime-parsin.patch - Patch for 6.1 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.
Credits
-------
Thanks to Security Curious for reporting this!
Related
Alias · CVE (1)
- CVE-2021-22902 The actionpack ruby gem (a framework for handling and responding to web requests in Rails) before 6.0.3.7, 6.1.3.2 suffers from a possible… vulnerability
Weakness · CWE (1)
- CWE-400 Uncontrolled Resource Consumption weakness
References
- https://nvd.nist.gov/vuln/detail/CVE-2021-22902 advisory
- https://hackerone.com/reports/1138654 web
- https://discuss.rubyonrails.org/t/cve-2021-22902-possible-denial-of-service-vulnerability-in-action-dispatch/77866 web
- https://github.com/rails/rails/releases/tag/v6.0.3.7 web
- https://github.com/rails/rails/releases/tag/v6.1.3.2 web
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2021-22902.yml web
- https://groups.google.com/g/rubyonrails-security/c/_5ID_ld9u1c web