CVE-2026-110803
Received
Received - Intake
Session Lock Denial of Service in Vaadin Framework 8
Vulnerability report for CVE-2026-110803, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-21
Last updated on: 2026-10-21
Assigner: Vaadin Ltd.
Description
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
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| vaadin | framework | 8.16.0 |
| vaadin | framework | 8.18.0 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-667 | The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors. |
| CWE-400 | The product does not properly control the allocation and maintenance of a limited resource. |
