CVE-2018-11406
HIGHCVE-2018-11406 is a high-severity (CVSS 8.8) Cross-Site Request Forgery (CSRF) vulnerability in symfony/symfony. O3 Security confirms whether CVE-2018-11406 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Symfony CSRF Token Fixation
Blast Radius
symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/security-bundle🐘symfony/security-bundle🐘symfony/security-bundle+12 moreReal-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
An issue was discovered in the Security component in Symfony 2.7.x before 2.7.48, 2.8.x before 2.8.41, 3.3.x before 3.3.17, 3.4.x before 3.4.11, and 4.0.x before 4.0.11. By default, a user's session is invalidated when the user is logged out. This behavior can be disabled through the invalidate_session option. In this case, CSRF tokens were not erased during logout which allowed for CSRF token fixation.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/symfony | ≥ 2.7.0&&< 2.7.48 | 2.7.48 |
| 🐘Packagist | symfony/symfony | ≥ 2.8.0&&< 2.8.41 | 2.8.41 |
| 🐘Packagist | symfony/symfony | ≥ 3.0.0&&< 3.3.17 | 3.3.17 |
| 🐘Packagist | symfony/symfony | ≥ 3.4.0&&< 3.4.11 | 3.4.11 |
| 🐘Packagist | symfony/symfony | ≥ 4.0.0&&< 4.0.11 | 4.0.11 |
| 🐘Packagist | symfony/security-bundle | ≥ 2.7.0&&< 2.7.48 | 2.7.48 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/symfony. 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 symfony/symfony to 2.7.48 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-11406 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-2018-11406 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-2018-11406. 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-2018-11406 in your dependencies?
O3 detects CVE-2018-11406 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.