GHSA-3gv2-29qc-v67m is a medium-severity (CVSS 6.3) CWE-384 vulnerability in symfony/security-bundle. A fix is available for symfony/security-bundle — see the affected versions and patch details below.
Symfony vulnerable to Session Fixation of CSRF tokens
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-3gv2-29qc-v67m.
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.
How urgent is this, really
GHSA-3gv2-29qc-v67m plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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 | 4.4.50composer require symfony/security-bundle:^4.4.50 |
| 🐘Packagist | symfony/security-bundle | ≥ 5.0.0&&< 5.4.20 | 5.4.20composer require symfony/security-bundle:^5.4.20 |
| 🐘Packagist | symfony/security-bundle | ≥ 6.0.0&&< 6.0.20 | 6.0.20composer require symfony/security-bundle:^6.0.20 |
| 🐘Packagist | symfony/security-bundle | ≥ 6.1.0&&< 6.1.12 | 6.1.12composer require symfony/security-bundle:^6.1.12 |
| 🐘Packagist | symfony/security-bundle | ≥ 6.2.0&&< 6.2.6 | 6.2.6composer require symfony/security-bundle:^6.2.6 |
| 🐘Packagist | symfony/symfony | ≥ 2.0.0&&< 4.4.50 | 4.4.50composer require symfony/symfony:^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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-3gv2-29qc-v67m can be triaged on real exposure rather than presence alone.
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.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is GHSA-3gv2-29qc-v67m in your dependencies?
O3 Security finds GHSA-3gv2-29qc-v67m across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.