GHSA-3gv2-29qc-v67m
MEDIUMSymfony vulnerable to Session Fixation of CSRF tokens
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.
Blast Radius
symfony/security-bundle🐘symfony/security-bundle🐘symfony/security-bundle🐘symfony/security-bundle🐘symfony/security-bundle🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony+2 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
Description
When authenticating users Symfony by default regenerates the session ID upon login, but preserves the rest of session attributes. Because this does not clear CSRF tokens upon login, this might enables same-site attackers to bypass the CSRF protection mechanism by performing an attack similar to a session-fixation.
Resolution
Symfony removes all CSRF tokens from the session on successful login.
The patch for this issue is available here for branch 4.4.
Credits
We would like to thank Marco Squarcina for reporting the issue and Nicolas Grekas for fixing it.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/security-bundle | ≥ 2.0.0&&< 4.4.50 | 4.4.50 |
| 🐘Packagist | symfony/security-bundle | ≥ 5.0.0&&< 5.4.20 | 5.4.20 |
| 🐘Packagist | symfony/security-bundle | ≥ 6.0.0&&< 6.0.20 | 6.0.20 |
| 🐘Packagist | symfony/security-bundle | ≥ 6.1.0&&< 6.1.12 | 6.1.12 |
| 🐘Packagist | symfony/security-bundle | ≥ 6.2.0&&< 6.2.6 | 6.2.6 |
| 🐘Packagist | symfony/symfony | ≥ 2.0.0&&< 4.4.50 | 4.4.50 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/security-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 symfony/security-bundle to 4.4.50 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3gv2-29qc-v67m 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 GHSA-3gv2-29qc-v67m 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 GHSA-3gv2-29qc-v67m. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-3gv2-29qc-v67m in your dependencies?
O3 detects GHSA-3gv2-29qc-v67m across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.