CVE-2021-31407
HIGHOSGi applications using Vaadin 12-14 and 19 vulnerable to server classes and resources exposure
Blast Radius
com.vaadin:flow-server☕com.vaadin:flow-serverReal-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
Vulnerability in OSGi integration in com.vaadin:flow-server versions 1.2.0 through 2.4.7 (Vaadin 12.0.0 through 14.4.9), and 6.0.0 through 6.0.1 (Vaadin 19.0.0) allows attacker to access application classes and resources on the server via crafted HTTP request.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | com.vaadin:flow-server | ≥ 1.2.0&&< 2.4.8 | 2.4.8 |
| ☕Maven | com.vaadin:flow-server | ≥ 6.0.0&&< 6.0.1 | 6.0.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.vaadin:flow-server. 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.vaadin:flow-server to 2.4.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-31407 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-2021-31407 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-2021-31407. 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-2021-31407 in your dependencies?
O3 detects CVE-2021-31407 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.