Vaadin · Com.Vaadin:Flow-Server · CVE-2019-25027
**Name of the Vulnerable Software and Affected Versions**
com.vaadin:flow-server versions 1.0.0 through 1.0.10
com.vaadin:flow-server versions 1.1.0 through 1.4.2
**Description**
The issue is related to missing output sanitization in the default RouteNotFoundError view. This allows an attacker to execute malicious JavaScript via a crafted URL.
**Recommendations**
For com.vaadin:flow-server versions 1.0.0 through 1.0.10, update to a version outside of this range to resolve the issue.
For com.vaadin:flow-server versions 1.1.0 through 1.4.2, update to a version outside of this range to resolve the issue.
As a temporary workaround, consider implementing proper output sanitization for the RouteNotFoundError view to prevent malicious JavaScript execution.