CVE-2020-4038
Reflected XSS in GraphQL Playground
GraphQL Playground (graphql-playground-html NPM package) before version 1.6.22 have a severe XSS Reflection attack vulnerability. All unsanitized user input passed into renderPlaygroundPage() method could trigger this vulnerability. This has been patched in graphql-playground-html version 1.6.22. Note that some of the associated dependent middleware packages are also affected including but not limited to graphql-playground-middleware-express before version 1.7.16, graphql-playground-middleware-koa before version 1.6.15, graphql-playground-middleware-lambda before version 1.7.17, and graphql-playground-middleware-hapi before 1.6.13.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
7.4
Reflected XSS in GraphQL Playground
GraphQL Playground (graphql-playground-html NPM package) before version 1.6.22 have a severe XSS Reflection attack vulnerability. All unsanitized user input passed into renderPlaygroundPage() method could trigger this vulnerability. This has been patched in graphql-playground-html version 1.6.22. Note that some of the associated dependent middleware packages are also affected including but not limited to graphql-playground-middleware-express before version 1.7.16, graphql-playground-middleware-koa before version 1.6.15, graphql-playground-middleware-lambda before version 1.7.17, and graphql-playground-middleware-hapi before 1.6.13.
- Record
CVE-2020-4038- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2020-0456
7.4
GraphQL Playground (graphql-playground-html NPM package) before version 1.6.22 have a severe XSS Reflection attack vulnerability. All unsanitized user input passed into renderPlaygroundPage() method could trigger this vulnerability. This has been patched in graphql-playground-html version 1.6.22. Note that some of the associated dependent middleware packages are also affected including but not limited to graphql-playground-middleware-express before version 1.7.16, graphql-playground-middleware-koa before version 1.6.15, graphql-playground-middleware-lambda before version 1.7.17, and graphql-playground-middleware-hapi before 1.6.13.
- Record
EUVD-2020-0456- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4852-vrh7-28rf
7.4
Reflected XSS in GraphQL Playground
Impact
directly impacted:
graphql-playground-html@<1.6.22- all unsanitized user input forrenderPlaygroundPage()
all of our consuming packages of graphql-playground-html are impacted:
graphql-playground-middleware-express@<1.7.16- unsanitized user input toexpressPlayground()graphql-playground-middleware-koa@<1.6.15- unsanitized user input tokoaPlayground()graphql-playground-middleware-lambda@<1.7.17- unsanitized user input tolambdaPlayground()graphql-playground-middleware-hapi@<1.6.13- unsanitized user input tohapiPlayground()
as well as any other packages that use these methods with unsanitized user input.
not impacted:
graphql-playground-electron- usesrenderPlaygroundPage()statically for a webpack build for electron bundle, no dynamic user inputgraphql-playground-react- usage of the component directly in a react application does not expose reflected XSS vulnerabilities. only the demo inpublic/contains the vulnerability, because it uses an old version of the html pacakge.
Patches
upgrading to the above mentioned versions will solve the issue.
If you're using graphql-playground-html directly, then:
yarn add graphql-playground-html@^1.6.22
or
npm install --save graphql-playground-html@^1.6.22
Then, similar steps need to be taken for each middleware:
Workarounds
Ensure you properly sanitize all user input for options you use for whatever function to initialize GraphQLPlayground:
for example, with graphql-playground-html and express:
const { sanitizeUrl } = require('@braintree/sanitize-url');
const qs = require('querystringify');
const { renderPlaygroundPage } = require('graphql-playground-html');
module.exports = (req, res, next) => {
const { endpoint } = qs.parse(req.url)
res.html(renderPlaygroundPage({endpoint: sanitizeUrl(endpoint) })).status(200)
next()
}
or, with graphql-playground-express:
const { expressPlayground } = require('graphql-playground-middleware-express');
const { sanitizeUrl } = require('@braintree/sanitize-url');
const qs = require('querystringify');
const { renderPlaygroundPage } = require('graphql-playground-html');
module.exports = (req, res, next) => {
const { endpoint } = qs.parse(req.url)
res.html(expressPlayground({endpoint: sanitizeUrl(endpoint) })).status(200)
next()
}
References
Credits
Masato Kinugawa of Cure53
For more information
If you have any questions or comments about this advisory:
- Open an issue in graphql-playground
- Email us at [email protected]
- Record
GHSA-4852-vrh7-28rf- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
7.4
GraphQL Playground (graphql-playground-html NPM package) before version 1.6.22 have a severe XSS Reflection attack vulnerability. All unsanitized user input passed into renderPlaygroundPage() method could trigger this vulnerability. This has been patched in graphql-playground-html version 1.6.22. Note that some of the associated dependent middleware packages are also affected including but not limited to graphql-playground-middleware-express before version 1.7.16, graphql-playground-middleware-koa before version 1.6.15, graphql-playground-middleware-lambda before version 1.7.17, and graphql-playground-middleware-hapi before 1.6.13.
- Record
CVE-2020-4038- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
7.4
GraphQL Playground (graphql-playground-html NPM package) before version 1.6.22 have a severe XSS Reflection attack vulnerability. All unsanitized user input passed into renderPlaygroundPage() method could trigger this vulnerability. This has been patched in graphql-playground-html version 1.6.22. Note that some of the associated dependent middleware packages are also affected including but not limited to graphql-playground-middleware-express before version 1.7.16, graphql-playground-middleware-koa before version 1.6.15, graphql-playground-middleware-lambda before version 1.7.17, and graphql-playground-middleware-hapi before 1.6.13.
- Record
CVE-2020-4038- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N - Updated
- 2026-11-02
OSVGHSA-4852-vrh7-28rf
7.4
Reflected XSS in GraphQL Playground
Impact
directly impacted:
graphql-playground-html@<1.6.22- all unsanitized user input forrenderPlaygroundPage()
all of our consuming packages of graphql-playground-html are impacted:
graphql-playground-middleware-express@<1.7.16- unsanitized user input toexpressPlayground()graphql-playground-middleware-koa@<1.6.15- unsanitized user input tokoaPlayground()graphql-playground-middleware-lambda@<1.7.17- unsanitized user input tolambdaPlayground()graphql-playground-middleware-hapi@<1.6.13- unsanitized user input tohapiPlayground()
as well as any other packages that use these methods with unsanitized user input.
not impacted:
graphql-playground-electron- usesrenderPlaygroundPage()statically for a webpack build for electron bundle, no dynamic user inputgraphql-playground-react- usage of the component directly in a react application does not expose reflected XSS vulnerabilities. only the demo inpublic/contains the vulnerability, because it uses an old version of the html pacakge.
Patches
upgrading to the above mentioned versions will solve the issue.
If you're using graphql-playground-html directly, then:
yarn add graphql-playground-html@^1.6.22
or
npm install --save graphql-playground-html@^1.6.22
Then, similar steps need to be taken for each middleware:
Workarounds
Ensure you properly sanitize all user input for options you use for whatever function to initialize GraphQLPlayground:
for example, with graphql-playground-html and express:
const { sanitizeUrl } = require('@braintree/sanitize-url');
const qs = require('querystringify');
const { renderPlaygroundPage } = require('graphql-playground-html');
module.exports = (req, res, next) => {
const { endpoint } = qs.parse(req.url)
res.html(renderPlaygroundPage({endpoint: sanitizeUrl(endpoint) })).status(200)
next()
}
or, with graphql-playground-express:
const { expressPlayground } = require('graphql-playground-middleware-express');
const { sanitizeUrl } = require('@braintree/sanitize-url');
const qs = require('querystringify');
const { renderPlaygroundPage } = require('graphql-playground-html');
module.exports = (req, res, next) => {
const { endpoint } = qs.parse(req.url)
res.html(expressPlayground({endpoint: sanitizeUrl(endpoint) })).status(200)
next()
}
References
Credits
Masato Kinugawa of Cure53
For more information
If you have any questions or comments about this advisory:
- Open an issue in graphql-playground
- Email us at [email protected]
- Record
GHSA-4852-vrh7-28rf- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
graphql-playground-htmlnpm |
before 1.6.22 | 1.6.22 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, products | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-4038 is a high vulnerability (CVSS 7.4) in Graphql Graphql-playground, published June 8, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 7.24%, the 94th percentile. Fixed in graphql-playground-html 1.6.22.
References
github.com/prisma-labs/graphql-playground/security/advisories/GHSA-4852-vrh7-28rf
github.com/prisma-labs/graphql-playground/commit/bf1883db538c97b076801a60677733816cb3cfb7
github.com/prisma-labs/graphql-playground
nvd.nist.gov/vuln/detail/CVE-2020-4038
github.com/graphql/graphql-playground/security/advisories/GHSA-4852-vrh7-28rf
github.com/advisories/GHSA-4852-vrh7-28rf