CVE-2026-2742 — MEDIUM (5.3)

Q: How severe is CVE-2026-2742?

CVE-2026-2742 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.

Q: Is there a patch for CVE-2026-2742?

Check the references section above for vendor advisories and patch information. Affected products include: Vaadin Vaadin.

Vulnerability 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.

CVSS Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

LOW

Availability

NONE

Affected Products

Vendor	Product	Versions
Vaadin	Vaadin	>= 10.0.0, < 14.14.1

Related Weaknesses (CWE)

CWE-284

References

https://github.com/vaadin/flow/pull/22998Issue TrackingPatch
https://github.com/vaadin/flow/pull/23033Issue TrackingPatch
https://github.com/vaadin/flow/pull/23034Issue TrackingPatch
https://github.com/vaadin/flow/pull/23037Issue TrackingPatch
https://github.com/vaadin/flow/pull/23052Issue TrackingPatch
https://github.com/vaadin/flow/pull/23057Issue TrackingPatch
https://vaadin.com/security/cve-2026-2742Vendor Advisory

FAQ

What is CVE-2026-2742?

CVE-2026-2742 is a vulnerability with a CVSS score of 5.3 (MEDIUM). 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 incons...

How severe is CVE-2026-2742?

CVE-2026-2742 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-2742?

Check the references section above for vendor advisories and patch information. Affected products include: Vaadin Vaadin.