CVE-2020-26238 is a high-severity (CVSS 8.1) CWE-74 vulnerability in com.cronutils:cron-utils. 2 public exploit references exist, so weaponization risk is real. O3 Security confirms whether CVE-2020-26238 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Template injection 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 parse, validate, migrate crons as well as get human readable descriptions for them. In cron-utils before version 9.1.3, a template Injection vulnerability is present. This enables attackers to inject arbitrary Java EL expressions, leading to unauthenticated Remote Code Execution (RCE) vulnerability. Only projects using the @Cron annotation to validate untrusted Cron expressions are affected. This issue was patched in version 9.1.3.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | com.cronutils:cron-utils | all versions | 9.1.3 |
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 9.1.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-26238 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-2020-26238 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-2020-26238. 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-2020-26238 in your dependencies?
O3 detects CVE-2020-26238 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.