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HIGH severity

CVE-2021-31409 — vaadin-compatibility-serv…

HIGHFix: vaadin/framework#12241

CVE-2021-31409 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in com.vaadin:vaadin-compatibility-server. A fix is available for com.vaadin:vaadin-compatibility-server — see the affected versions and patch details below.

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

Also known asGHSA-c332-w4jm-55wv
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.7%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs76th percentile — riskier than 76% of all scored CVEsHighest risk
0.22%0.87%1.52%2.17%0.7%1.7%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-31409 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
☕com.vaadin:vaadin-compatibility-server

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavencom.vaadin:vaadin-compatibility-server≥ 8.0.0&&< 8.13.08.13.0com.vaadin:vaadin-compatibility-server:8.13.0

Affected Products

1 product · 1 configurations
Application
vaadinvaadin
≥ 8.0.0 && ≤ 8.12.4
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.vaadin:vaadin-compatibility-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update com.vaadin:vaadin-compatibility-server to 8.13.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-31409 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

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CVE-2021-31409: vaadin-compatibility — Fixed in 8.13.0