CVE-2021-21234 is a high-severity (CVSS 7.7) Path Traversal vulnerability in eu.hinsch:spring-boot-actuator-logview. 2 public exploit references exist, so weaponization risk is real. O3 Security confirms whether CVE-2021-21234 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Directory Traversal in spring-boot-actuator-logview
Real-World Exposure
eu.hinsch:spring-boot-actuator-logviewReal-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
spring-boot-actuator-logview in a library that adds a simple logfile viewer as spring boot actuator endpoint. It is maven package "eu.hinsch:spring-boot-actuator-logview". In spring-boot-actuator-logview before version 0.2.13 there is a directory traversal vulnerability. The nature of this library is to expose a log file directory via admin (spring boot actuator) HTTP endpoints. Both the filename to view and a base folder (relative to the logging folder root) can be specified via request parameters. While the filename parameter was checked to prevent directory traversal exploits (so that filename=../somefile would not work), the base folder parameter was not sufficiently checked, so that filename=somefile&base=../ could access a file outside the logging base directory). The vulnerability has been patched in release 0.2.13. Any users of 0.2.12 should be able to update without any issues as there are no other changes in that release. There is no workaround to fix the vulnerability other than updating or removing the dependency. However, removing read access of the user the application is run with to any directory not required for running the application can limit the impact. Additionally, access to the logview endpoint can be limited by deploying the application behind a reverse proxy.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | eu.hinsch:spring-boot-actuator-logview | all versions | 0.2.13 |
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 eu.hinsch:spring-boot-actuator-logview. 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 eu.hinsch:spring-boot-actuator-logview to 0.2.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21234 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-2021-21234 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-2021-21234. 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-2021-21234 in your dependencies?
O3 detects CVE-2021-21234 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.