# CVE-2021-41249: XSS vulnerability in GraphQL Playground

> Attackers can execute arbitrary JavaScript in users' browsers via malicious GraphQL schemas, potentially stealing credentials.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 4 Nov 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-59r9-6jp6-jcm7

## What is CVE-2021-41249?

CVE-2021-41249 is a high-severity cross-site scripting vulnerability in graphql-playground, published on 4 Nov 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

GraphQL Playground is a GraphQL IDE for development of graphQL focused applications. All versions of graphql-playground-react older than graphql-playground-react@1.7.28 are vulnerable to compromised HTTP schema introspection responses or schema prop values with malicious GraphQL type names, exposing a dynamic XSS attack surface that can allow code injection on operation autocomplete. In order for the attack to take place, the user must load a malicious schema in graphql-playground. There are several ways this can occur, including by specifying the URL to a malicious schema in the endpoint query parameter. If a user clicks on a link to a GraphQL Playground installation that specifies a malicious server, arbitrary JavaScript can run in the user's browser, which can be used to exfiltrate user credentials or other harmful goals. If you are using graphql-playground-react directly in your client app, upgrade to version 1.7.28 or later.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2021-41249?

2 open source packages ship an affected version, including graphql-playground-react. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `graphql-playground-react` | npm | All versions | 1.7.28 |
| `graphql-playground-react` | npm | All versions | 1.7.28 |

Products: Graphql Playground.

## How do I fix CVE-2021-41249?

Upgrade graphql-playground-react to 1.7.28 or later.

## Is CVE-2021-41249 being exploited?

There is no known exploitation of CVE-2021-41249 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41249 and fix it if it is affected.

What it is: CVE-2021-41249 is a high-severity cross-site scripting vulnerability in graphql-playground, published on 4 Nov 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-41249 in the wild and no public exploit code.

Affected packages and fixed versions:
- graphql-playground-react (npm): affected all versions; fixed in 1.7.28
- graphql-playground-react (npm): affected all versions; fixed in 1.7.28

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-41249/ (Markdown: https://insights.sbomify.com/CVE-2021-41249/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41249
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41249
- OSV: https://osv.dev/vulnerability/CVE-2021-41249

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-41249/
Summaries are generated and may contain mistakes; the official description above is the record.