CVE-2021-37626
HIGHCVE-2021-37626 is a high-severity (CVSS 7.2) Code Injection vulnerability in contao/core-bundle. O3 Security confirms whether CVE-2021-37626 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
PHP file inclusion via insert tags
Real-World Exposure
contao/core-bundle🐘contao/core-bundle🐘contao/core-bundle🐘contao/contao🐘contao/contao🐘contao/contaoReal-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
Contao is an open source CMS that allows you to create websites and scalable web applications. In affected versions it is possible to load PHP files by entering insert tags in the Contao back end. Installations are only affected if they have untrusted back end users who have the rights to modify fields that are shown in the front end. Update to Contao 4.4.56, 4.9.18 or 4.11.7 to resolve. If you cannot update then disable the login for untrusted back end users.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | contao/core-bundle | ≥ 4.0.0&&< 4.4.56 | 4.4.56 |
| 🐘Packagist | contao/core-bundle | ≥ 4.5.0&&< 4.9.18 | 4.9.18 |
| 🐘Packagist | contao/core-bundle | ≥ 4.10.0&&< 4.11.7 | 4.11.7 |
| 🐘Packagist | contao/contao | ≥ 4.0.0&&< 4.4.56 | 4.4.56 |
| 🐘Packagist | contao/contao | ≥ 4.5.0&&< 4.9.18 | 4.9.18 |
| 🐘Packagist | contao/contao | ≥ 4.10.0&&< 4.11.7 | 4.11.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for contao/core-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 contao/core-bundle to 4.4.56 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-37626 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-2021-37626 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-2021-37626. 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-2021-37626 in your dependencies?
O3 detects CVE-2021-37626 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.