CVE-2026-41570 is a high-severity (CVSS 7.8) remote code execution vulnerability in phpunit/phpunit. O3 Security confirms whether CVE-2026-41570 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
PHPUnit: Argument injection via newline in PHP INI values forwarded to child processes
Real-World Exposure
phpunit/phpunit🐘phpunit/phpunitReal-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
PHPUnit is a testing framework for PHP. In versions 12.5.21 and 13.1.5, PHPUnit forwards PHP INI settings to child processes (used for isolated/PHPT test execution) as -d name=value command-line arguments without neutralizing INI metacharacters. Because PHP's INI parser interprets " as a string delimiter, ; as the start of a comment, and most importantly a newline as a directive separator, a value containing a newline is parsed by the child process as multiple INI directives. An attacker able to influence a single INI value can therefore inject arbitrary additional directives into the child's configuration, including auto_prepend_file, extension, disable_functions, open_basedir, and others. Setting auto_prepend_file to an attacker-controlled path yields remote code execution in the child process. This issue has been patched in versions 12.5.22 and 13.1.6.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | phpunit/phpunit | ≥ 12.5.21&&< 12.5.22 | 12.5.22 |
| 🐘Packagist | phpunit/phpunit | ≥ 13.1.5&&< 13.1.6 | 13.1.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phpunit/phpunit. 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 phpunit/phpunit to 12.5.22 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-41570 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 CVE-2026-41570 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 CVE-2026-41570. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-41570 in your dependencies?
O3 detects CVE-2026-41570 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.