CVE-2020-35217: Eclipse Vert.x-Web

High severity, CVSS 8.8. EPSS: 0.6% chance of exploitation in the next 30 days.

Vert.x-Web framework v4.0 milestone 1-4 does not perform a correct CSRF verification. Instead of comparing the CSRF token in the request with the CSRF token in the cookie, it compares the CSRF token in the cookie against a CSRF token that is stored in the session. An attacker does not even need to provide a CSRF token in the request because the framework does not consider it. The cookies are automatically sent by the browser and the verification will always succeed, leading to a successful CSRF attack.

Affected products

• Eclipse Vert.x-Web: version 4.0.0 only

Published 2021-01-20. Last modified 2026-06-17.