CVE-2026-2742: Unauthorized session creation via reserved framework path access

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-10 · updated 2026-06-17
Weakness: CWE-284

Description

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.

Affected products

Vaadin: from 10.0.0 before 14.14.1; from 15.0.0 before 23.6.7; from 24.0.0 before 24.9.8; from 25.0.0 before 25.0.2 — fixed in 14.14.1, 23.6.7, 24.9.8, 25.0.2

How to fix

Upgrade to a fixed version: Vaadin 14.14.1, 23.6.7, 24.9.8, 25.0.2. Check the vendor advisory for mitigations.

References

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