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💎 RubyGems

GHSA-qxmr-qxh6-2cc9

HIGH

ReDos vulnerability on guest checkout email validation

Also known asCVE-2021-43805
Published
Dec 7, 2021
Updated
Mar 13, 2026
Affected
3 pkgs
Patched
3 / 3
Exploits
1 known

EPSS Exploitation Probability

via FIRST.org ↗
1.4%probability of exploitation in next 30 days
Lower Risk69th percentile+1.29%
0.00%0.63%1.27%1.90%0.1%1.4%Dec 25Apr 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

3 pkgs affected
💎solidus_core💎solidus_core💎solidus_core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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..

Before the patch, it can be reproduced in the console like this:

irb(main)> Spree::EmailValidator::EMAIL_REGEXP.match "[email protected].@"
processing time: 54.293660s
=> nil

To reproduce in the browser, fill in the "Customer Email" field with that fake email address during a guest checkout. Before that, you should open the browser dev tools and change the type attribute for that field from email to text. After entering a fake address and pressing the "Save & Continue" button, the browser will take a long term to perform the request before showing an error message for the invalid address. Eventually, making the email string even longer could lead to the exhaustion of server resources.

Patches

Versions 3.1.4, 3.0.4, and 2.11.13 have been patched to use a different regular expression.

There's an improbable chance that some orders in your system end up having associated an email address that is no longer valid. We've added a task to check precisely that:

bin/rails solidus:check_orders_with_invalid_email

The above will print information for every affected order if any.

Workarounds

If a prompt upgrade is not an option, please, add the following to config/application.rb:

config.after_initialize do
  Spree::EmailValidator.send(:remove_const, :EMAIL_REGEXP)
  Spree::EmailValidator::EMAIL_REGEXP = URI::MailTo::EMAIL_REGEXP
end

References

For more information

If you have any questions or comments about this advisory:

Affected Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemssolidus_coreall versions2.11.13
💎RubyGemssolidus_core3.0.0&&< 3.0.43.0.4
💎RubyGemssolidus_core3.1.0&&< 3.1.43.1.4
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for solidus_core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update solidus_core to 2.11.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qxmr-qxh6-2cc9 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-qxmr-qxh6-2cc9 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-qxmr-qxh6-2cc9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact 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.`. Before the patch, it can be reproduced in the console like this: ```ruby irb(main)> Spree::EmailValidator::EMAIL_REGEXP.match "[email protected].@" processing time: 54.293660s => nil ``` To reproduce in the browser, fill in the "Customer Email" field with that fake email address during a guest checkout. Before that, you shoul
O3 Security · Impact-Aware SCA

Is GHSA-qxmr-qxh6-2cc9 in your dependencies?

O3 detects GHSA-qxmr-qxh6-2cc9 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.