CVE-2021-41120 is a high-severity (CVSS 7.5) Information Exposure vulnerability in sylius/paypal-plugin. A fix is available for sylius/paypal-plugin — see the affected versions and patch details below.
Sylius PayPal Plugin allows unauthorized access to Credit card form, exposing payer name and not requiring 3DS
EPSS Exploitation Probability
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.
How urgent is this, really
CVE-2021-41120 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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
Impact
URL to the payment page done after checkout was created with autoincremented payment id (/pay-with-paypal/{id}) and therefore it was easy to access for anyone, not even the order's customer. The problem was, the Credit card form has prefilled "credit card holder" field with the Customer's first and last name.
Additionally, the mentioned form did not require a 3D Secure authentication, as well as did not checked the result of the 3D Secure authentication.
Patches
The problem has been patched in Sylius/PayPalPlugin 1.2.4 and 1.3.1
Workarounds
One 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.
For more information
If you have any questions or comments about this advisory:
- Open an issue in Sylius/PayPalPlugin issues
- Email us at security at sylius dot com
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | sylius/paypal-plugin | ≥ 1.0.0&&< 1.2.4 | 1.2.4composer require sylius/paypal-plugin:^1.2.4 |
| 🐘Packagist | sylius/paypal-plugin | ≥ 1.3.0&&< 1.3.1 | 1.3.1composer require sylius/paypal-plugin:^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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2021-41120 can be triaged on real exposure rather than presence alone.
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 Security finds CVE-2021-41120 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.