CVE-2025-9467: 
Java vulnerability analysis and mitigation

CVE-2025-9467 is a vulnerability in Vaadin Upload's start listener functionality that allows bypassing file upload validation on the server-side. The vulnerability was disclosed on September 4, 2025, and affects multiple versions of Vaadin products including Vaadin 7.0.0-7.7.47, 8.0.0-8.28.1, 14.0.0-14.13.0, 23.0.0-23.6.1, and 24.0.0-24.7.6 (Vaadin Advisory).

The vulnerability is classified as an Improper Input Validation (CWE-20) issue with a CVSS v4.0 base score of 5.3 (Medium). The attack vector is network-based (AV:N) with low attack complexity (AC:L), requiring low privileges (PR:L) and no user interaction (UI:N). The vulnerability can lead to limited impact on integrity (VI:L) and availability (VA:L) with no impact on confidentiality (VC:N) (Vaadin Advisory).

When exploited, this vulnerability allows attackers to bypass server-side validation mechanisms for file uploads in Vaadin applications. This could potentially lead to unauthorized file uploads, affecting the integrity and availability of the application (Snyk).

Users are advised to upgrade to the fixed versions: Vaadin 7.7.48, 8.28.2, 14.13.1, 23.6.2, or 24.7.7 or newer. For Vaadin Upload Flow component, users should upgrade to versions 14.13.1, 23.6.2, or 24.7.7 or newer. Note that Vaadin versions 10-13 and 15-22 are no longer supported and users should update to the latest 14, 23, or 24 version (Vaadin Advisory).