CVE-2021-41269 is a critical-severity (CVSS 9.8) Code Injection vulnerability in com.cronutils:cron-utils. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2021-41269 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Critical vulnerability found in cron-utils
Real-World Exposure
com.cronutils:cron-utilsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
cron-utils is a Java library to define, parse, validate, migrate crons as well as get human readable descriptions for them. In affected versions A template Injection was identified in cron-utils enabling attackers to inject arbitrary Java EL expressions, leading to unauthenticated Remote Code Execution (RCE) vulnerability. Versions up to 9.1.2 are susceptible to this vulnerability. Please note, that only projects using the @Cron annotation to validate untrusted Cron expressions are affected. The issue was patched and a new version was released. Please upgrade to version 9.1.6. There are no known workarounds known.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | com.cronutils:cron-utils | all versions | 9.1.6 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.cronutils:cron-utils. 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 com.cronutils:cron-utils to 9.1.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41269 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-2021-41269 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-2021-41269. 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-2021-41269 in your dependencies?
O3 detects CVE-2021-41269 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.