Improper Locking Affecting com.vaadin:vaadin-server package, versions [8.16.0,8.32.2)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JAVA-COMVAADIN-21691526
- published24 Oct 2026
- disclosed21 Oct 2026
- creditMichal Legocki
Introduced: 21 Oct 2026
NewCVE-2026-110803 (opens in a new tab)How to fix?
Upgrade com.vaadin:vaadin-server to version 8.32.2 or higher.
Overview
com.vaadin:vaadin-server is a Java framework for modern Java web applications.
Affected versions of this package are vulnerable to Improper Locking due to the improper release of a session lock in the VaadinService.requestEnd process when handling a non-numeric v-uiId request parameter. An attacker can cause the application to become unresponsive by sending requests with a malformed v-uiId value, which leads to session locks not being released and eventually exhausts the server's thread pool. No authentication is required, as a session cookie can be obtained with a single request.
Workaround
This vulnerability can be mitigated by rejecting requests whose v-uiId parameter is not an integer before they are handled, by overriding VaadinServlet.service() and responding with a 400 status for such requests.