CVE-2021-41120 is a high-severity (CVSS 7.5) Information Exposure vulnerability in sylius/paypal-plugin. O3 Security confirms whether CVE-2021-41120 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Sylius PayPal Plugin allows unauthorized access to Credit card form, exposing payer name and not requiring 3DS
Real-World Exposure
sylius/paypal-plugin🐘sylius/paypal-pluginReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
sylius/paypal-plugin is a paypal plugin for the Sylius development platform. In affected versions the URL to the payment page done after checkout was created with autoincremented payment id (/pay-with-paypal/{id}) and therefore it was easy to predict. The problem is that the Credit card form has prefilled "credit card holder" field with the Customer's first and last name and hence this can lead to personally identifiable information exposure. Additionally, the mentioned form did not require authentication. The problem has been patched in Sylius/PayPalPlugin 1.2.4 and 1.3.1. If users are unable to update they can override a sylius_paypal_plugin_pay_with_paypal_form route and change its URL parameters to (for example) {orderToken}/{paymentId}, then override the Sylius\PayPalPlugin\Controller\PayWithPayPalFormAction service, to operate on the payment taken from the repository by these 2 values. It would also require usage of custom repository method. Additionally, one could override the @SyliusPayPalPlugin/payWithPaypal.html.twig template, to add contingencies: ['SCA_ALWAYS'] line in hostedFields.submit(...) function call (line 421). It would then have to be handled in the function callback.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | sylius/paypal-plugin | ≥ 1.0.0&&< 1.2.4 | 1.2.4 |
| 🐘Packagist | sylius/paypal-plugin | ≥ 1.3.0&&< 1.3.1 | 1.3.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sylius/paypal-plugin. 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.
Fix
Update sylius/paypal-plugin to 1.2.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41120 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 pinpoints whether CVE-2021-41120 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 CVE-2021-41120. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-41120 in your dependencies?
O3 detects CVE-2021-41120 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.