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HIGH severity

CVE-2021-31408 — vaadin-bom

HIGHFix: vaadin/flow#10577

CVE-2021-31408 is a high-severity (CVSS 7.1) CWE-613 vulnerability in com.vaadin:vaadin-bom. A fix is available for com.vaadin:vaadin-bom — see the affected versions and patch details below.

Server session is not invalidated when logout() helper method of Authentication module is used in Vaadin 18-19

Also known asGHSA-mr8h-j9cv-4m8h
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs24th percentile — riskier than 24% of all scored CVEsHighest risk
0.00%0.27%0.55%0.82%0.0%0.3%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2021-31408 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 395,249 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-bom

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

Authentication.logout() helper in com.vaadin:flow-client versions 5.0.0 prior to 6.0.0 (Vaadin 18), and 6.0.0 through 6.0.4 (Vaadin 19.0.0 through 19.0.3) uses incorrect HTTP method, which, in combination with Spring Security CSRF protection, allows local attackers to access Fusion endpoints after the user attempted to log out.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavencom.vaadin:vaadin-bom≥ 18.0.0&&< 19.0.419.0.4com.vaadin:vaadin-bom:19.0.4

Affected Products

2 products · 4 configurations
Application
flowvaadin
≥ 6.0.0 && < 6.0.5
range
Application
vaadinvaadin
≥ 19.0.0 && < 19.0.4
1 version
18.0.0

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-bom, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update com.vaadin:vaadin-bom to 19.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-31408 is resolved across your whole dependency graph.

  3. Workarounds

    Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

`Authentication.logout()` helper in `com.vaadin:flow-client` versions 5.0.0 prior to 6.0.0 (Vaadin 18), and 6.0.0 through 6.0.4 (Vaadin 19.0.0 through 19.0.3) uses incorrect HTTP method, which, in combination with Spring Security CSRF protection, allows local attackers to access Fusion endpoints after the user attempted to log out. - https://vaadin.com/security/cve-2021-31408
O3 Security · Impact-Aware SCA

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CVE-2021-31408: vaadin-bom CSRF — Fixed in 19.0.4