Reflected XSS in GraphQL Playground

Exploitation

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

CVSS

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

EPSS

• CVE-2020-4038: 7.24% estimated exploitation activity in the next 30 days; percentile 94.34 (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.

Impact directly impacted: - graphql-playground-html@<1.6.22 - all unsanitized user input for renderPlaygroundPage() all of our consuming packages of graphql-playground-html are impacted: - graphql-playground-middleware-express@<1.7.16 - unsanitized user input to expressPlayground() - graphql-playground-middleware-koa@<1.6.15 - unsanitized user input to koaPlayground() - graphql-playground-middleware-lambda@<1.7.17 - unsanitized user input to lambdaPlayground() - graphql-playground-middleware-hapi@<1.6.13 - unsanitized user input to hapiPlayground() as well as any other packages that use these methods with unsanitized user input. not impacted: - graphql-playground-electron - uses renderPlaygroundPage() statically for a webpack build for electron bundle, no dynamic user input - graphql-playground-react - usage of the component directly in a react application does not expose reflected XSS vulnerabilities. only the demo in public/ contains the vulnerability, because it uses an old…

Published by the source

9 Jun 2020, 00:24 UTC

Last modified by the source

8 Jul 2026, 05:59 UTC

Source last checked

26 Oct 2026, 12:07 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-4852-vrh7-28rf

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-4852-vrh7-28rf

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# Patch Next advisory brief: CVE-2020-4038

Advisory: Reflected XSS in GraphQL Playground
IDs: CVE-2020-4038, GHSA-4852-vrh7-28rf
Record: https://patchnext.com/advisories/cve-2020-4038 (revision 2, source checked 26 Oct 2026, 12:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: graphql-playground-html 1.6.22. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm graphql-playground-html: affected < 1.6.22; fixed in 1.6.22

## Suggested inspection (read-only)
- `npm ls graphql-playground-html --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## 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 graphql-playground-html.
- 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://osv.dev/vulnerability/GHSA-4852-vrh7-28rf (OSV record GHSA-4852-vrh7-28rf lists affected ranges: npm graphql-playground-html >=0 <1.6.22 (fixed))
- Verified: https://github.com/advisories/GHSA-4852-vrh7-28rf (GitHub-reviewed advisory GHSA-4852-vrh7-28rf lists affected ranges: npm graphql-playground-html >=0 <1.6.22)

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