CVE-2026-110737: Push Endpoint Returns Permissive CORS Headers

Severity: low (CVSS 2.3 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-27 · updated 2026-10-27
Weakness: CWE-346

Description

The push endpoint of a Vaadin application that uses server push reflects the request Origin into the Access-Control-Allow-Origin response header and allows credentials, because Flow configures Atmosphere with DROP_ACCESS_CONTROL_ALLOW_ORIGIN_HEADER set to false and its CorsInterceptor then echoes whatever Origin the request carries. A page on any origin can therefore make a cross origin request to that endpoint with the user's cookies and read the response, although reading anything useful also requires the push identifier of that session. Applications that do not use @Push are not affected, and neither is the WebSocket transport. The behaviour was introduced in January 2015 and is present in every Flow release and in Vaadin Framework from 7.1.0, which is when push was added. Users of affected versions should apply the following mitigation or upgrade. Releases that have fixed this issue include: Product version Vaadin 14.14.0 - 14.14.7 Vaadin 23.6.0 - 23.6.16 Vaadin 24.4.0 - 24.4.25 Vaadin 24.5.0 - 24.5.15 Vaadin 24.6.0 - 24.6.13 Vaadin 24.7.0 - 24.7.16 Vaadin 24.8.0 - 24.8.17 Vaadin 24.9.0 - 24.9.23 Vaadin 24.10.0 - 24.10.11 Vaadin 25.0.0 - 25.0.13 Vaadin 25.1.0 - 25.1.13 Vaadin 25.2.0 - 25.2.10 Vaadin 25.3.0 - 25.3.2 Vaadin Framework 7.1.0 - 7.7.54 Vaadin Framework 8.0.0 - 8.32.1 Mitigation Upgrade to 14.14.8 Upgrade to 23.6.17 Upgrade to 24.4.26 Upgrade to 24.7.17 Upgrade to 24.7.17 Upgrade to 24.7.17 Upgrade to 24.9.24 Upgrade to 24.9.24 Upgrade to 24.10.12 Upgrade to 25.2.11 Upgrade to 25.2.11 Upgrade to 25.2.11 Upgrade to 25.3.3 Upgrade to 7.7.55 Upgrade to 8.32.2 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. Artifacts under com.vaadin Maven coordinates / Vulnerable versions / Fixed version vaadin / 14.14.0 - 14.14.7 / >=14.14.8 vaadin / 23.6.0 - 23.6.16 / >=23.6.17 vaadin / 24.4.0 - 24.4.25 / >=24.4.26 vaadin / 24.5.0 - 24.5.15 / >=24.7.17 vaadin / 24.6.0 - 24.6.13 / >=24.7.17 vaadin / 24.7.0 - 24.7.16 / >=24.7.17 vaadin / 24.8.0 - 24.8.17 / >=24.9.24 vaadin / 24.9.0 - 24.9.23 / >=24.9.24 vaadin / 24.10.0 - 24.10.11 / >=24.10.12 vaadin / 25.0.0 - 25.0.13 / >=25.2.11 vaadin / 25.1.0 - 25.1.13 / >=25.2.11 vaadin / 25.2.0 - 25.2.10 / >=25.2.11 vaadin / 25.3.0 - 25.3.2 / >=25.3.3 vaadin-core / 14.14.0 - 14.14.7 / >=14.14.8 vaadin-core / 23.6.0 - 23.6.16 / >=23.6.17 vaadin-core / 24.4.0 - 24.4.25 / >=24.4.26 vaadin-core / 24.5.0 - 24.5.15 / >=24.7.17 vaadin-core / 24.6.0 - 24.6.13 / >=24.7.17 vaadin-core / 24.7.0 - 24.7.16 / >=24.7.17 vaadin-core / 24.8.0 - 24.8.17 / >=24.9.24 vaadin-core / 24.9.0 - 24.9.23 / >=24.9.24 vaadin-core / 24.10.0 - 24.10.11 / >=24.10.12 vaadin-core / 25.0.0 - 25.0.13 / >=25.2.11 vaadin-core / 25.1.0 - 25.1.13 / >=25.2.11 vaadin-core / 25.2.0 - 25.2.10 / >=25.2.11 vaadin-core / 25.3.0 - 25.3.2 / >=25.3.3 flow-server / 2.13.0 - 2.13.7 / >=2.13.8 flow-server / 23.6.0 - 23.6.15 / >=23.6.16 flow-server / 24.4.0 - 24.4.18 / >=24.4.19 flow-server / 24.5.0 - 24.5.17 / >=24.7.17 flow-server / 24.6.0 - 24.6.14 / >=24.7.17 flow-server / 24.7.0 - 24.7.15 / >=24.7.16 flow-server / 24.8.0 - 24.8.16 / >=24.9.24 flow-server / 24.9.0 - 24.9.28 / >=24.9.29 flow-server / 24.10.0 - 24.10.14 / >=24.10.15 flow-server / 25.0.0 - 25.0.15 / >=25.2.11 flow-server / 25.1.0 - 25.1.18 / >=25.1.19 flow-server / 25.2.0 - 25.2.12 / >=25.2.13 flow-server / 25.3.0 - 25.3.3 / >=25.3.4 vaadin-server / 7.1.0 - 7.7.54 / >=7.7.55 vaadin-server / 8.0.0 - 8.32.1 / >=8.32.2 vaadin-server-mpr-jakarta / 7.7.36 - 7.7.54 / >=7.7.55 vaadin-server-mpr-jakarta / 8.18.0 - 8.32.1 / >=8.32.2

Affected products

vaadin flow: from 2.13.0 before 2.13.8; from 23.6.0 before 23.6.16; from 24.4.0 before 24.4.19; from 24.5.0 through 24.5.17; from 24.6.0 through 24.6.14; from 24.7.0 before 24.7.16 — fixed in 2.13.8, 23.6.16, 24.4.19, 24.7.16, 24.9.29, 24.10.15
vaadin framework: from 7.1.0 before 7.7.55; from 8.0.0 before 8.32.2 — fixed in 7.7.55, 8.32.2
Vaadin: from 14.14.0 before 14.14.8; from 23.6.0 before 23.6.17; from 24.4.0 before 24.4.26; from 24.5.0 through 24.5.15; from 24.6.0 through 24.6.13; from 24.7.0 before 24.7.17 — fixed in 14.14.8, 23.6.17, 24.4.26, 24.7.17, 24.9.24, 24.10.12

How to fix

Upgrade to a fixed version: vaadin flow 2.13.8, 23.6.16, 24.4.19, 24.7.16; vaadin framework 7.7.55, 8.32.2; Vaadin 14.14.8, 23.6.17, 24.4.26, 24.7.17. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-110737 or the next vulnerability affects your stack