CVE-2020-5220
MEDIUMCVE-2020-5220 is a medium-severity (CVSS 5.3) CWE-444 vulnerability in sylius/resource-bundle. O3 Security confirms whether CVE-2020-5220 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Ability to expose data in Sylius by using an unintended serialisation group
Real-World Exposure
sylius/resource-bundle🐘sylius/resource-bundle🐘sylius/resource-bundle🐘sylius/sylius🐘sylius/sylius🐘sylius/resource-bundleReal-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 ResourceBundle accepts and uses any serialisation groups to be passed via a HTTP header. This might lead to data exposure by using an unintended serialisation group - for example it could make Shop API use a more permissive group from Admin API. Anyone exposing an API with ResourceBundle's controller is affected. The vulnerable versions are: <1.3 || >=1.3.0 <=1.3.12 || >=1.4.0 <=1.4.5 || >=1.5.0 <=1.5.0 || >=1.6.0 <=1.6.2. The patch is provided for Sylius ResourceBundle 1.3.13, 1.4.6, 1.5.1 and 1.6.3, but not for any versions below 1.3.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | sylius/resource-bundle | ≥ 1.4.0&&< 1.4.6 | 1.4.6 |
| 🐘Packagist | sylius/resource-bundle | ≥ 1.5.0&&< 1.5.1 | 1.5.1 |
| 🐘Packagist | sylius/resource-bundle | ≥ 1.6.0&&< 1.6.3 | 1.6.3 |
| 🐘Packagist | sylius/sylius | all versions | 1.3.12 |
| 🐘Packagist | sylius/sylius | ≥ 1.4.0&&< 1.4.4 | 1.4.4 |
| 🐘Packagist | sylius/resource-bundle | ≥ 1.0.0&&< 1.3.13 | 1.3.13 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sylius/resource-bundle. 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/resource-bundle to 1.4.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-5220 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-2020-5220 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-2020-5220. 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-2020-5220 in your dependencies?
O3 detects CVE-2020-5220 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.