CVE-2021-43805: ReDos vulnerability on guest checkout email validation

Severity: medium (CVSS 5.0 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-12-07 · updated 2026-06-17
Weakness: CWE-1333

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 The maintainers added a check for email addresses that are no longer valid that will print information about any affected orders that exist.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.

Affected products

solidusio solidus: before 2.11.13; from 3.0.0 before 3.0.4; from 3.1.0 before 3.1.4 — fixed in 2.11.13, 3.0.4, 3.1.4

How to fix

Upgrade to a fixed version: solidusio solidus 2.11.13, 3.0.4, 3.1.4. Check the vendor advisory for mitigations.

References

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