CVE-2025-9467: 
Java vulnerability analysis and mitigation

CVE-2025-9467 is a security vulnerability affecting Vaadin Upload's start listener functionality. The vulnerability was discovered and disclosed on September 3, 2025, affecting multiple versions of Vaadin, including versions 7.0.0 through 24.7.6. The issue allows attackers to bypass file upload validation on the server-side, impacting the security of file upload processes (Vaadin Security).

The vulnerability is classified as CWE-20 (Improper Input Validation) 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 impacts both integrity and availability at a low level (VI:L, VA:L) with no confidentiality impact (VC:N) (Vaadin Security).

When exploited, the vulnerability allows attackers to bypass the upload validation mechanisms implemented in the Vaadin Upload's start listener. This bypass could potentially lead to unauthorized file uploads and compromise the security of applications using affected Vaadin versions (Vaadin Security).

Vaadin has released patches for all affected versions. Users are advised to upgrade to the following fixed versions: Vaadin 7.7.48 for 7.x users, 8.28.2 for 8.x users, 14.13.1 for 14.x users, 23.6.2 for 23.x users, and 24.7.7 or newer for 24.x users. Users of versions 10-13 and 15-22 should upgrade to the latest supported version (14, 23, or 24) as these versions are no longer supported (Vaadin Security).