CVE-2020-1960
MEDIUMCVE-2020-1960 is a medium-severity (CVSS 4.7) vulnerability in org.apache.flink:flink-core. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2020-1960 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Command injection in Apache Flink
Real-World Exposure
org.apache.flink:flink-core☕org.apache.flink:flink-coreReal-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
A vulnerability in Apache Flink (1.1.0 to 1.1.5, 1.2.0 to 1.2.1, 1.3.0 to 1.3.3, 1.4.0 to 1.4.2, 1.5.0 to 1.5.6, 1.6.0 to 1.6.4, 1.7.0 to 1.7.2, 1.8.0 to 1.8.3, 1.9.0 to 1.9.2, 1.10.0) where, when running a process with an enabled JMXReporter, with a port configured via metrics.reporter.reporter_name>.port, an attacker with local access to the machine and JMX port can execute a man-in-the-middle attack using a specially crafted request to rebind the JMXRMI registry to one under the attacker's control. This compromises any connection established to the process via JMX, allowing extraction of credentials and any other transferred data.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.flink:flink-core | all versions | 1.9.3 |
| ☕Maven | org.apache.flink:flink-core | ≥ 1.10.0&&< 1.10.1 | 1.10.1 |
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 org.apache.flink:flink-core. 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 org.apache.flink:flink-core to 1.9.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-1960 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-2020-1960 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-2020-1960. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is CVE-2020-1960 in your dependencies?
O3 detects CVE-2020-1960 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.