There is a possible DoS vulnerability in the Token Authentication logic in Action Controller. This vulnerability has been assigned the CVE identifier CVE-2021-22904.
Versions Affected: >= 4.0.0 Not affected: < 4.0.0 Fixed Versions: 184.108.40.206, 220.127.116.11, 18.104.22.168, 5.2.6
Impacted code uses
authenticate_with_http_token for request authentication. Impacted code will
look something like this:
class PostsController < ApplicationController before_action :authenticate private def authenticate authenticate_or_request_with_http_token do |token, options| # ... end end end
All users running an affected release should either upgrade or use one of the workarounds immediately.
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 ActionController::HttpAuthentication::Token AUTHN_PAIR_DELIMITERS = /(?:,|;|\t)/ 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.
- 5-2-http-authentication-dos.patch - Patch for 5.2 series
- 6-0-http-authentication-dos.patch - Patch for 6.0 series
- 6-1-http-authentication-dos.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.
Thank you to HackerOne for reporting this issue!