CVE-2019-25027 in Vaadin
Summary
by MITRE • 04/24/2021
Missing output sanitization in default RouteNotFoundError view in com.vaadin:flow-server versions 1.0.0 through 1.0.10 (Vaadin 10.0.0 through 10.0.13), and 1.1.0 through 1.4.2 (Vaadin 11.0.0 through 13.0.5) allows attacker to execute malicious JavaScript via crafted URL
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Analysis
by VulDB Data Team • 04/29/2021
The vulnerability identified as CVE-2019-25027 represents a critical security flaw in the Vaadin framework's default error handling mechanism. This issue affects multiple versions of the flow-server component, specifically those ranging from 1.0.0 through 1.0.10 and 1.1.0 through 1.4.2, which correspond to Vaadin versions 10.0.0 through 10.0.13 and 11.0.0 through 13.0.5 respectively. The vulnerability stems from inadequate output sanitization within the default RouteNotFoundError view implementation, creating a path for cross-site scripting attacks that can be exploited through carefully crafted URL parameters.
The technical flaw manifests in the way the framework handles routing errors when a requested URL does not correspond to any defined route within the application. When such an error occurs, the default RouteNotFoundError view is rendered to the user, but this view fails to properly sanitize or escape any user-provided input that might be included in the URL path. This omission allows attackers to inject malicious JavaScript code directly into the error page through URL parameters, bypassing normal input validation mechanisms that would typically protect against such attacks. The vulnerability is particularly dangerous because it operates at the framework level, affecting all applications built using the affected Vaadin versions regardless of their specific implementation details.
The operational impact of this vulnerability is significant, as it provides attackers with a reliable vector for executing arbitrary JavaScript code within the context of the victim's browser session. This can lead to various security consequences including session hijacking, data theft, credential harvesting, and potential full system compromise if the affected application has elevated privileges. The attack requires minimal sophistication as it only necessitates crafting a malicious URL with JavaScript payload in the path parameters, making it particularly dangerous in environments where users might encounter error pages or where applications are exposed to untrusted input. The vulnerability affects the entire Vaadin ecosystem, potentially impacting thousands of applications that rely on this framework for their web interface components.
Organizations affected by this vulnerability should immediately upgrade to patched versions of the Vaadin framework, specifically versions that have been released to address this output sanitization issue. The recommended mitigation strategy involves comprehensive version updates across all affected applications, followed by thorough security testing to ensure proper sanitization of all user inputs. Additionally, implementing proper input validation at multiple layers of the application architecture can provide additional defense-in-depth measures. This vulnerability aligns with CWE-79, which specifically addresses Cross-site Scripting flaws, and maps to ATT&CK technique T1211 where adversaries leverage application vulnerabilities to execute malicious code. Security teams should also consider implementing web application firewalls and content security policies as supplementary protective measures to detect and prevent exploitation attempts.