{"id":"GHSA-4852-vrh7-28rf","summary":"Reflected XSS in GraphQL Playground","details":"### Impact\n\n**directly impacted:**\n\n- `graphql-playground-html@\u003c1.6.22` - all unsanitized user input for `renderPlaygroundPage()`\n\n**all of our consuming packages** of `graphql-playground-html` are impacted:\n\n- `graphql-playground-middleware-express@\u003c1.7.16` - unsanitized user input to `expressPlayground()`\n- `graphql-playground-middleware-koa@\u003c1.6.15` - unsanitized user input to `koaPlayground()`\n- `graphql-playground-middleware-lambda@\u003c1.7.17` - unsanitized user input to `lambdaPlayground()`\n- `graphql-playground-middleware-hapi@\u003c1.6.13` - unsanitized user input to `hapiPlayground()`\n\nas well as ***any other packages*** that use these methods with unsanitized user input.\n\n**not impacted:**\n\n- `graphql-playground-electron` - uses `renderPlaygroundPage()` statically for a webpack build for electron bundle, no dynamic user input\n- `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 version of the html pacakge.\n\n### Patches\n\nupgrading to the above mentioned versions will solve the issue.\n\nIf you're using `graphql-playground-html` directly, then:\n\n```\nyarn add graphql-playground-html@^1.6.22\n```\n\nor\n\n```\nnpm install --save graphql-playground-html@^1.6.22\n```\n\nThen, similar steps need to be taken for each middleware:\n\n- [Upgrade Express Middleware](https://www.npmjs.com/package/graphql-playground-middleware-express#security-upgrade-steps)\n- [Upgrade Koa Middleware](https://www.npmjs.com/package/graphql-playground-middleware-koa#security-upgrade-steps)\n- [Upgrade Lambda Middleware](https://www.npmjs.com/package/graphql-playground-middleware-lambda#security-upgrade-steps)\n- [Upgrade Hapi Middleware](https://www.npmjs.com/package/graphql-playground-middleware-hapi#security-upgrade-steps)\n\n### Workarounds\n\nEnsure you properly sanitize *all* user input for options you use for whatever function to initialize GraphQLPlayground:\n\nfor example, with `graphql-playground-html` and express:\n\n```js\nconst { sanitizeUrl } = require('@braintree/sanitize-url');\n\nconst qs = require('querystringify');\n\nconst { renderPlaygroundPage } = require('graphql-playground-html');\n\nmodule.exports = (req, res, next) =\u003e {\n\tconst { endpoint } = qs.parse(req.url)\n\tres.html(renderPlaygroundPage({endpoint: sanitizeUrl(endpoint) })).status(200)\n\tnext()\n}\n```\n\nor, with `graphql-playground-express`:\n\n```js\nconst { expressPlayground } = require('graphql-playground-middleware-express');\nconst { sanitizeUrl } = require('@braintree/sanitize-url');\n\nconst qs = require('querystringify');\n\nconst { renderPlaygroundPage } = require('graphql-playground-html');\n\nmodule.exports = (req, res, next) =\u003e {\n\tconst { endpoint } = qs.parse(req.url)\n\tres.html(expressPlayground({endpoint: sanitizeUrl(endpoint) })).status(200)\n\tnext()\n}\n```\n\n### References\n\n- [OWASP: How to Test for CSS Reflection Attacks](https://github.com/OWASP/wstg/blob/master/document/4-Web_Application_Security_Testing/07-Input_Validation_Testing/01-Testing_for_Reflected_Cross_Site_Scripting.md)\n- [Original Report from Cure53](https://user-images.githubusercontent.com/1368727/84191028-dfb7b980-aa65-11ea-8e18-4b8706f538e2.jpg) (jpg)\n\n\n### Credits\n\nMasato Kinugawa of Cure53\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [graphql-playground](https://github.com/prisma-labs/graphql-playground/issues/new/choose)\n* Email us at [rikki.schulte@gmail.com](mailto:rikki.schulte@gmail.com)\n","aliases":["CVE-2020-4038"],"modified":"2026-07-08T05:59:49.227442073Z","published":"2020-06-09T00:24:57Z","database_specific":{"nvd_published_at":null,"cwe_ids":["CWE-79"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2020-06-08T20:27:53Z"},"references":[{"type":"WEB","url":"https://github.com/graphql/graphql-playground/security/advisories/GHSA-4852-vrh7-28rf"},{"type":"WEB","url":"https://github.com/prisma-labs/graphql-playground/security/advisories/GHSA-4852-vrh7-28rf"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-4038"},{"type":"WEB","url":"https://github.com/prisma-labs/graphql-playground/commit/bf1883db538c97b076801a60677733816cb3cfb7"},{"type":"WEB","url":"https://github.com/prisma-labs/graphql-playground#security-details"}],"affected":[{"package":{"name":"graphql-playground-html","ecosystem":"npm","purl":"pkg:npm/graphql-playground-html"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.6.22"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2020/06/GHSA-4852-vrh7-28rf/GHSA-4852-vrh7-28rf.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N"}]}