FlawAtlas
Search the atlas
CVE-2021-22902 High

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 denial of service vulnerability in the Mime type parser of Action Dispatch. Carefully crafted Accept headers can cause the mime type parser in Action Dispatch to do catastrophic backtracking in the regular expression engine.

Exploit probability 2.8%
Published June 11, 2021
Required by Not available
Last source change August 7, 2026

02 / AFFECTED SOFTWARE

Affected packages

Unknown Unknown

9 explicit affected versions

RubyGems actionpack

22 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities GHSA-g8ww-46x2-2p65

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 <[email protected]> for reporting this!

View original source
Open Source Vulnerabilities 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 denial of service vulnerability in the Mime type parser of Action Dispatch. Carefully crafted Accept headers can cause the mime type parser in Action Dispatch to do catastrophic backtracking in the regular expression engine.

View original source

05 / REFERENCES

Further evidence