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MEDIUM severity

CVE-2020-36319 — flow-server

MEDIUMFix: vaadin/flow#8016

CVE-2020-36319 is a medium-severity (CVSS 6.5) Information Exposure vulnerability in com.vaadin:flow-server. A fix is available for com.vaadin:flow-server — see the affected versions and patch details below.

Potential sensitive data exposure in applications using Vaadin 15

Also known asGHSA-rjww-2x8v-m9v9
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.0%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs62th percentile — riskier than 62% of all scored CVEsHighest risk
0.00%0.50%1.00%1.50%0.4%1.0%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2020-36319 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:flow-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

Insecure configuration of default ObjectMapper in com.vaadin:flow-server versions 3.0.0 through 3.0.5 (Vaadin 15.0.0 through 15.0.4) may expose sensitive data if the application also uses e.g. @RestController

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavencom.vaadin:flow-server≥ 3.0.0&&< 3.0.63.0.6com.vaadin:flow-server:3.0.6

Affected Products

2 products · 2 configurations
Application
flowvaadin
≥ 3.0.0 && < 3.0.6
range
Application
vaadinvaadin
≥ 15.0.0 && < 15.0.5
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:flow-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update com.vaadin:flow-server to 3.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-36319 is resolved across your whole dependency graph.

  3. Workarounds

    Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Frequently Asked Questions

Insecure configuration of default `ObjectMapper` in `com.vaadin:flow-server` versions 3.0.0 through 3.0.5 (Vaadin 15.0.0 through 15.0.4) may expose sensitive data if the application also uses e.g. `@RestController` - https://vaadin.com/security/cve-2020-36319
O3 Security · Impact-Aware SCA

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CVE-2020-36319: flow-server — Fixed in 3.0.6