CVE-2026-2742: Unauthorized session creation via reserved framework path access
An authentication bypass vulnerability exists in Vaadin 14.0.0 through 14.14.0, 23.0.0 through 23.6.6, 24.0.0 through 24.9.7 and 25.0.0 through 25.0.1, applications using Spring Security due to inconsistent path pattern matching of reserved framework paths.
Accessing the /VAADIN endpoint without a trailing slash bypasses security filters, and allowing unauthenticated users to trigger framework initialization and create sessions without proper authorization.
Users of affected versions using Spring Security should upgrade as follows: 14.0.0-14.14.0 upgrade to 14.14.1, 23.0.0-23.6.6 to 23.6.7, 24.0.0 - 24.9.7 to 24.9.8, and 25.0.0-25.0.1 upgrade to 25.0.2 or newer.
Please note that Vaadin versions 10-13 and 15-22 are no longer supported and users should update either to the latest 14, 23, 24, 25 version.
Other sources
An authentication bypass vulnerability exists in Vaadin 14.0.0 through 14.14.0, 23.0.0 through 23.6.6, 24.0.0 through 24.9.7 and 25.0.0 through 25.0.1, applications using Spring Security due to inconsistent path pattern matching of reserved framework paths.
Accessing the /VAADIN endpoint without a trailing slash bypasses security filters, and allowing unauthenticated users to trigger framework initialization and create sessions without proper authorization.
Users of affected versions using Spring Security should upgrade as follows: 14.0.0-14.14.0 upgrade to 14.14.1, 23.0.0-23.6.6 to 23.6.7, 24.0.0 - 24.9.7 to 24.9.8, and 25.0.0-25.0.1 upgrade to 25.0.2 or newer.
Please note that Vaadin versions 10-13 and 15-22 are no longer supported and you should update either to the latest 14, 23, 24, 25 version.
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Frequently Asked Questions
What is the severity of CVE-2026-2742?
CVE-2026-2742 is classified as a medium severity authentication bypass vulnerability.
How do I fix CVE-2026-2742?
To fix CVE-2026-2742, upgrade your Vaadin application to a version that is not affected, specifically above 14.14.0, 23.6.6, 24.9.7, or 25.0.1.
Which versions of Vaadin are affected by CVE-2026-2742?
CVE-2026-2742 affects Vaadin versions 14.0.0 to 14.14.0, 23.0.0 to 23.6.6, 24.0.0 to 24.9.7, and 25.0.0 to 25.0.1.
Can CVE-2026-2742 lead to unauthorized access?
Yes, CVE-2026-2742 can potentially allow unauthorized session creation, leading to unauthorized access.
Is CVE-2026-2742 specific to any frameworks?
CVE-2026-2742 is specifically an issue for applications using Vaadin in conjunction with Spring Security.