ReDos vulnerability on guest checkout email validation

Vulnerability Description

Solidus is a free, open-source ecommerce platform built on Rails. Versions of Solidus prior to 3.1.4, 3.0.4, and 2.11.13 have a denial of service vulnerability that could be exploited during a guest checkout. The regular expression used to validate a guest order's email was subject to exponential backtracking through a fragment like `a.a.` Versions 3.1.4, 3.0.4, and 2.11.13 have been patched to use a different regular expression. The maintainers added a check for email addresses that are no longer valid that will print information about any affected orders that exist. If a prompt upgrade is not an option, a workaround is available. It is possible to edit the file `config/application.rb` manually (with code provided by the maintainers in the GitHub Security Advisory) to check email validity.

References

• https://github.com/solidusio/solidus/security/advisories/GHSA-qxmr-qxh6-2cc9
• https://github.com/solidusio/solidus/commit/9867153e01e3c3b898cdbcedd7b43375ea922401