CVE-2019-18889 — cache
CRITICALCVE-2019-18889 is a critical-severity (CVSS 9.8) Code Injection vulnerability in symfony/cache. EPSS puts its 30-day exploitation probability at 33.2% (98th percentile). A fix is available for symfony/cache — see the affected versions and patch details below.
Symfony Unsafe Cache Serialization Could Enable RCE
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2019-18889 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 384,534 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
symfony/cache🐘symfony/cache🐘symfony/cache🐘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
An issue was discovered in Symfony 3.4.0 through 3.4.34, 4.2.0 through 4.2.11, and 4.3.0 through 4.3.7. Serializing certain cache adapter interfaces could result in remote code injection. This is related to symfony/cache.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/cache | ≥ 3.1.0&&< 3.4.35 | 3.4.35composer require symfony/cache:^3.4.35 |
| 🐘Packagist | symfony/cache | ≥ 4.0.0&&< 4.2.12 | 4.2.12composer require symfony/cache:^4.2.12 |
| 🐘Packagist | symfony/cache | ≥ 4.3.0&&< 4.3.8 | 4.3.8composer require symfony/cache:^4.3.8 |
| 🐘Packagist | symfony/symfony | ≥ 3.1.0&&< 3.4.35 | 3.4.35composer require symfony/symfony:^3.4.35 |
| 🐘Packagist | symfony/symfony | ≥ 4.0.0&&< 4.2.12 | 4.2.12composer require symfony/symfony:^4.2.12 |
| 🐘Packagist | symfony/symfony | ≥ 4.3.0&&< 4.3.8 | 4.3.8composer require symfony/symfony:^4.3.8 |
Affected Products
fedorafedoraprojectsymfonysensiolabsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/cache, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update symfony/cache to 3.4.35 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-18889 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
Frequently Asked Questions
Is CVE-2019-18889 in your dependencies?
Find it across Packagist, including transitive dependencies.