Regular expression Denial of Service (ReDoS) in EmailValidator class in V7 compatibility module in Vaadin 8

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2021-31409: 1.67% estimated exploitation activity in the next 30 days; percentile 76.84 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Unsafe validation RegEx in EmailValidator component in com.vaadin:vaadin-compatibility-server versions 8.0.0 through 8.12.4 (Vaadin versions 8.0.0 through 8.12.4) allows attackers to cause uncontrolled resource consumption by submitting malicious email addresses.

Published by the source

4 May 2021, 17:42 UTC

Last modified by the source

1 Feb 2023, 05:05 UTC

Source last checked

26 Oct 2026, 16:06 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-c332-w4jm-55wv

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# Patch Next advisory brief: CVE-2021-31409

Advisory: Regular expression Denial of Service (ReDoS) in EmailValidator class in V7 compatibility module in Vaadin 8
IDs: CVE-2021-31409, GHSA-c332-w4jm-55wv
Record: https://patchnext.com/advisories/cve-2021-31409 (revision 1, source checked 26 Oct 2026, 16:06 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: com.vaadin:vaadin-compatibility-server 8.13.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven com.vaadin:vaadin-compatibility-server: affected >= 8.0.0, < 8.13.0; fixed in 8.13.0

## Suggested inspection (read-only)
- Maven com.vaadin:vaadin-compatibility-server: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on com.vaadin:vaadin-compatibility-server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-c332-w4jm-55wv (GitHub-reviewed advisory GHSA-c332-w4jm-55wv lists affected ranges: Maven com.vaadin:vaadin-compatibility-server >=8.0.0 <8.13.0)

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