CVE-2016-1902 is a high-severity (CVSS 7.5) CWE-310 vulnerability in symfony/security-core. A fix is available for symfony/security-core — see the affected versions and patch details below.
Symfony Cryptographic Vulnerability
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
symfony/security-core🐘symfony/security-core🐘symfony/security🐘symfony/security🐘symfony/security🐘symfony/symfony🐘symfony/symfony🐘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
The nextBytes function in the SecureRandom class in Symfony before 2.3.37, 2.6.x before 2.6.13, and 2.7.x before 2.7.9 does not properly generate random numbers when used with PHP 5.x without the paragonie/random_compat library and the openssl_random_pseudo_bytes function fails, which makes it easier for attackers to defeat cryptographic protection mechanisms via unspecified vectors.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/security-core | ≥ 2.4.0&&< 2.6.13 | 2.6.13composer require symfony/security-core:^2.6.13 |
| 🐘Packagist | symfony/security-core | ≥ 2.7.0&&< 2.7.9 | 2.7.9composer require symfony/security-core:^2.7.9 |
| 🐘Packagist | symfony/security | ≥ 2.3.0&&< 2.3.37 | 2.3.37composer require symfony/security:^2.3.37 |
| 🐘Packagist | symfony/security | ≥ 2.4.0&&< 2.6.13 | 2.6.13composer require symfony/security:^2.6.13 |
| 🐘Packagist | symfony/security | ≥ 2.7.0&&< 2.7.9 | 2.7.9composer require symfony/security:^2.7.9 |
| 🐘Packagist | symfony/symfony | ≥ 2.3.0&&< 2.3.37 | 2.3.37composer require symfony/symfony:^2.3.37 |
Affected Products
debian linuxdebiansymfonysensiolabsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/security-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update symfony/security-core to 2.6.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-1902 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.
Frequently Asked Questions
Is CVE-2016-1902 in your dependencies?
Find it across Packagist, including transitive dependencies.