Vulnerability Description
VaadinService.requestEnd() in Vaadin Framework 8 locks the session and then reads the v-uiId request parameter outside the block that releases the lock. A request carrying a non-numeric v-uiId makes Integer.parseInt throw while the session lock is held, so the lock is never released and the container thread returns to its pool still owning it. Every later request to that session then blocks forever in VaadinService.lockSession(), and repeating the request exhausts the thread pool and takes the application down. No authentication is required: a session cookie, which any client obtains with a single request, is enough. Vaadin 10 and later are not affected, because Flow releases the lock in a finally block and does not read that parameter there, and Vaadin Framework 7 is not affected either. Users of affected versions should apply the following mitigation or upgrade. Releases that have fixed this issue include: Product version Vaadin Framework 8.16.0 - 8.32.1 Mitigation Upgrade to 8.32.2 Vaadin Framework 7 and Vaadin 10 and later do not carry this behaviour and need no upgrade for this issue. Artifacts Maven coordinates / Vulnerable versions / Fixed version com.vaadin:vaadin-server / 8.16.0 - 8.32.1 / >=8.32.2 com.vaadin:vaadin-server-mpr-jakarta / 8.18.0 - 8.32.1 / >=8.32.2
Related Weaknesses (CWE)
References
FAQ
What is CVE-2026-110803?
CVE-2026-110803 is a documented vulnerability. VaadinService.requestEnd() in Vaadin Framework 8 locks the session and then reads the v-uiId request parameter outside the block that releases the lock. A request carrying a non-numeric v-uiId makes I...
How severe is CVE-2026-110803?
CVSS scoring is not yet available for CVE-2026-110803. Check NVD for updates.
Is there a patch for CVE-2026-110803?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.