CVE-2020-27216
HIGHLocal Temp Directory Hijacking Vulnerability
Blast Radius
org.eclipse.jetty:jetty-webapp☕org.mortbay.jetty:jetty-webapp☕org.eclipse.jetty:jetty-webapp☕org.mortbay.jetty:jetty-webapp☕org.eclipse.jetty:jetty-webapp☕org.mortbay.jetty:jetty-webappReal-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
In Eclipse Jetty versions 1.0 thru 9.4.32.v20200930, 10.0.0.alpha1 thru 10.0.0.beta2, and 11.0.0.alpha1 thru 11.0.0.beta2O, on Unix like systems, the system's temporary directory is shared between all users on that system. A collocated user can observe the process of creating a temporary sub directory in the shared temporary directory and race to complete the creation of the temporary subdirectory. If the attacker wins the race then they will have read and write permission to the subdirectory used to unpack web applications, including their WEB-INF/lib jar files and JSP files. If any code is ever executed out of this temporary directory, this can lead to a local privilege escalation vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.eclipse.jetty:jetty-webapp | all versions | 9.4.33.v20201020 |
| ☕Maven | org.mortbay.jetty:jetty-webapp | all versions | 9.4.33 |
| ☕Maven | org.eclipse.jetty:jetty-webapp | ≥ 10.0.0.beta1&&< 10.0.0.beta3 | 10.0.0.beta3 |
| ☕Maven | org.mortbay.jetty:jetty-webapp | ≥ 10.0.0.beta1&&< 10.0.0.beta3 | 10.0.0.beta3 |
| ☕Maven | org.eclipse.jetty:jetty-webapp | ≥ 11.0.0.beta1&&< 11.0.0.beta3 | 11.0.0.beta3 |
| ☕Maven | org.mortbay.jetty:jetty-webapp | ≥ 11.0.0.beta1&&< 11.0.0.beta3 | 11.0.0.beta3 |
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.eclipse.jetty:jetty-webapp. 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.eclipse.jetty:jetty-webapp to 9.4.33.v20201020 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-27216 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-2020-27216 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-2020-27216. 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-2020-27216 in your dependencies?
O3 detects CVE-2020-27216 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.