How severe is CVE-2020-6506?

CVE-2020-6506 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2020-6506?

CVE-2020-6506 affects the following packages: react-native-webview (npm). Ecosystems affected: npm.

How do I fix CVE-2020-6506?

Update react-native-webview to 11.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-6506 is resolved across your whole dependency graph.

How do I detect CVE-2020-6506 in my npm dependencies?

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

How do I mitigate CVE-2020-6506 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2020-6506 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-6506 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-6506?

CVE-2020-6506 has an EPSS (Exploit Prediction Scoring System) score of 3.7%, placing it in the 90th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2020-6506 published, and has it been updated?

CVE-2020-6506 was published on July 22, 2020 and was last updated on March 15, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

CVE-2020-6506 — react-native-webview

MEDIUMFix: react-native-webview/react-native-webview#1747

CVE-2020-6506 is a medium-severity (CVSS 6.5) vulnerability in react-native-webview. A fix is available for react-native-webview — see the affected versions and patch details below.

Android WebView Universal Cross-site Scripting

Also known asGHSA-36j3-xxf7-4pqg

Published

Jul 22, 2020

Updated

Mar 15, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

3.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs90th percentile — riskier than 90% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2020-6506 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 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

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

1Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

react-native-webviewnpm

5.4Mdownloads / week

Description

A universal cross-site scripting (UXSS) vulnerability, CVE-2020-6506 (https://crbug.com/1083819), has been identified in the Android WebView system component, which allows cross-origin iframes to execute arbitrary JavaScript in the top-level document. This vulnerability affects React Native apps which use a react-native-webview that allows navigation to arbitrary URLs, and when that app runs on systems with an Android WebView version prior to 83.0.4103.106.

Pending mitigation

Ensure users update their Android WebView system component via the Google Play Store to 83.0.4103.106 or higher to avoid this UXSS. 'react-native-webview' is working on a mitigation but it could take some time.

References

https://alesandroortiz.com/articles/uxss-android-webview-cve-2020-6506/

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`react-native-webview`	all versions	11.0.0`npm install react-native-webview@11.0.0`

Affected Products

1 product · 1 configurations

Application

chromegoogle

< 83.0.4103.106

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-native-webview, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update react-native-webview to 11.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-6506 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

Product	Fixed in	Advisory
Red Hat Enterprise Linux 6 Supplementary	`chromium-browser-0:83.0.4103.106-1.el6_10`	RHSA-2020:2643

Frequently Asked Questions

A universal cross-site scripting (UXSS) vulnerability, CVE-2020-6506 (https://crbug.com/1083819), has been identified in the Android WebView system component, which allows cross-origin iframes to execute arbitrary JavaScript in the top-level document. This vulnerability affects React Native apps which use a `react-native-webview` that allows navigation to arbitrary URLs, and when that app runs on systems with an Android WebView version prior to 83.0.4103.106. ## Pending mitigation Ensure users update their Android WebView system component via the Google Play Store to 83.0.4103.106 or higher

O3 Security · Impact-Aware SCA

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Find it across npm, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.5/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Raw vector

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

Weaponization

No known public exploit tooling found.

OpenSSF Scorecard

Package health score

react-native-webview

4.2/10

Code-Review1/10

Maintained10/10

Branch-ProtectionN/A

Assessed Oct 5, 2026

Timeline

Disclosed

Jul 22, 2020

Last updated

Mar 15, 2026

Identifiers

CVE-2020-6506

GHSA-36j3-xxf7-4pqg

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedMar 15, 2026

CVE-2020-6506 — react-native-webview

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Pending mitigation

References

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2020-6506 in your dependencies?