CVE-2018-11385
HIGHCVE-2018-11385 is a high-severity (CVSS 8.1) CWE-384 vulnerability in symfony/symfony. O3 Security confirms whether CVE-2018-11385 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Symfony Session Fixation Vulnerability
Real-World Exposure
symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/security-http🐘symfony/security-http🐘symfony/security-http+7 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. A session fixation vulnerability within the "Guard" login feature may allow an attacker to impersonate a victim towards the web application if the session id value was previously known to the attacker.
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-http | ≥ 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-2018-11385 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-2018-11385 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-2018-11385. 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-2018-11385 in your dependencies?
O3 detects CVE-2018-11385 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.