CVE-2021-32693 is a high-severity (CVSS 8.8) Improper Authentication vulnerability in symfony/security-http. A fix is available for symfony/security-http — see the affected versions and patch details below.
Authentication granted to all firewalls instead of just one
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-32693 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
symfony/security-http🐘symfony/symfonyReal-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 an application defines multiple firewalls, the authenticated token delivered by one of the firewalls is available to all other firewalls. This can be abused when the application defines different providers for different parts of an application. In such a situation, a user authenticated on one part of the application is considered authenticated on the whole application.
Resolution
We now ensure that the authenticated token is only available for the firewall that generates it.
The patch for this issue is available here for branch 5.3.
Credits
I would like to thank Bogdan, gndk, Paweł Warchoł, Warxcell, and Adrien Lamotte for reporting the issue and Wouter J for fixing the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/security-http | ≥ 5.3.0&&< 5.3.2 | 5.3.2composer require symfony/security-http:^5.3.2 |
| 🐘Packagist | symfony/symfony | ≥ 5.3.0&&< 5.3.2 | 5.3.2composer require symfony/symfony:^5.3.2 |
Affected Products
symfonysensiolabsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/security-http, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update symfony/security-http to 5.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32693 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2021-32693 in your dependencies?
Find it across Packagist, including transitive dependencies.