7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
0.001 Low
EPSS
Percentile
41.9%
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.
The fixed releases are available at the normal locations.
The following monkey patch placed in an initializer can be used to work around the issue.
module Mime
class Type
MIME_REGEXP = /\A(?:\*\/\*|#{MIME_NAME}\/(?:\*|#{MIME_NAME})(?>\s*#{MIME_PARAMETER}\s*)*)\z/
end
end
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.
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.
Thanks to Security Curious <security…@pm.me> for reporting this!
CPE | Name | Operator | Version |
---|---|---|---|
actionpack | eq | 6.0.2 | |
actionpack | eq | 6.0.3.3 | |
actionpack | eq | 6.0.2.rc2 | |
actionpack | eq | 6.1.2.1 | |
actionpack | eq | 6.0.3.5 | |
actionpack | eq | 6.0.3 | |
actionpack | eq | 6.0.0 | |
actionpack | eq | 6.0.3.rc1 | |
actionpack | eq | 6.1.0 | |
actionpack | eq | 6.1.3.1 |
discuss.rubyonrails.org/t/cve-2021-22902-possible-denial-of-service-vulnerability-in-action-dispatch/77866
github.com/rails/rails/releases/tag/v6.0.3.7
github.com/rails/rails/releases/tag/v6.1.3.2
github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2021-22902.yml
groups.google.com/g/rubyonrails-security/c/_5ID_ld9u1c
hackerone.com/reports/1138654
nvd.nist.gov/vuln/detail/CVE-2021-22902
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
0.001 Low
EPSS
Percentile
41.9%