Insecure Temporary Directory Usage in Vaadin 14 and 15-19
Summary
GHSA-c57f-4vp2-jqhm: Insecure temporary directory usage in frontend build functionality of Vaadin 14 and 15-19. Affects com.vaadin:flow-server across 2 version ranges.
>= 2.0.9, < 2.5.3
>= 3.0.0, < 6.0.6
Fixed in 2.5.3 or 6.0.6, depending on the release line you run. How to fix ↓
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Background
Vaadin is an open-source Java framework used for building modern web applications. It provides a set of user interface components and tools for creating responsive and interactive web interfaces. The com.vaadin:flow-server package is a core component of Vaadin that handles the server-side functionality of the framework. This vulnerability affects versions 2.0.9 through 2.5.2 (Vaadin 14.0.3 through Vaadin 14.5.2), 3.0 prior to 6.0 (Vaadin 15 prior to 19), and 6.0.0 through 6.0.5 (Vaadin 19.0.0 through 19.0.4).
Vulnerability Detail
The vulnerability arises from the insecure usage of temporary directories in the frontend build functionality of Vaadin. Local users can exploit this vulnerability to inject malicious code into frontend resources during application rebuilds. This can lead to various security risks, including remote code execution, unauthorized access to sensitive data, and privilege escalation. The vulnerability has a CVSS score of 6.3, indicating a moderate severity level.
How To Fix
Latest published version: 25.3.4 as of 23 Oct 2026
Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
>= 2.0.9, < 2.5.32.5.3 -
>= 3.0.0, < 6.0.66.0.6
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Workaround
There is no specific workaround mentioned for this vulnerability. It is recommended to follow the fix instructions and upgrade to the fixed versions of com.vaadin:flow-server.
Conclusion
Insecure temporary directory usage in the frontend build functionality of Vaadin 14 and 15-19 can allow local users to inject malicious code into frontend resources during application rebuilds. It is crucial to upgrade to the fixed versions of com.vaadin:flow-server to mitigate this vulnerability. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for com.vaadin:flow-server →
FAQ
Vaadin is an open-source Java framework for building web applications.
com.vaadin:flow-server is a package that handles the server-side functionality of Vaadin.
Versions 2.0.9 through 2.5.2 (Vaadin 14.0.3 through Vaadin 14.5.2), 3.0 prior to 6.0 (Vaadin 15 prior to 19), and 6.0.0 through 6.0.5 (Vaadin 19.0.0 through 19.0.4) are affected.
The vulnerability can lead to remote code execution, unauthorized access to sensitive data, and privilege escalation.
The CVSS score of this vulnerability is 6.3, indicating a moderate severity level.
References
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