# GHSA-2fvv-qxrq-7jq6: apollo-server-core vulnerable to URL-based XSS attack affecting IE11 on default landing page

> Attacker can execute JavaScript in IE11 via malicious URL on default landing page; upgrade Apollo Server or disable landing page.

- **Severity:** Not scored
- **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:** 18 Aug 2022

## What is GHSA-2fvv-qxrq-7jq6?

GHSA-2fvv-qxrq-7jq6 is a cross-site scripting vulnerability in apollo-server-core, published on 18 Aug 2022. 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

### Impact

The default landing page contained HTML to display a sample `curl` command which is made visible if the full landing page bundle could not be fetched from Apollo's CDN. The server's URL is directly interpolated into this command inside the browser from `window.location.href`. On some older browsers such as IE11, this value is not URI-encoded. On such browsers, opening a malicious URL pointing at an Apollo Router could cause execution of attacker-controlled JavaScript.

This only affects Apollo Server with the [default landing page](https://www.apollographql.com/docs/apollo-server/api/plugin/landing-pages/) enabled. Old browsers visiting your server may be affected if ANY of these apply:
- You do not pass any landing page plugin to the `plugins` option of `new ApolloServer`.
- You pass `ApolloServerPluginLandingPageLocalDefault()` or `ApolloServerPluginLandingPageProductionDefault()` to the `plugins` option of `new ApolloServer`.

Browsers visiting your server are NOT affected if ANY of these apply:
- You pass `ApolloServerPluginLandingPageDisabled()` to the `plugins` option of `new ApolloServer`.
- You pass `ApolloServerPluginLandingPageGraphQLPlayground()` to the `plugins` option of `new ApolloServer`.
- You pass a custom plugin implementing the `renderLandingPage` hook to the `plugins` option of `new ApolloServer`.

This issue was introduced in v3.0.0 when the landing page feature was added.

### Patches
To avoid this, the sample `curl` command has been removed in release 3.10.1.

### Workarounds

Disabling the landing page removes the possibility of exploit:

```ts
import { ApolloServerPluginLandingPageDisabled } from 'apollo-server-core';

new ApolloServer({
  plugins: [ApolloServerPluginLandingPageDisabled()],
  // ...
});
```

### See also
A similar issue exists in the landing page of Apollo Router. See the corresponding [Apollo Router security advisory](https://github.com/apollographql/router/security/advisories/GHSA-p5q6-hhww-f999).

### For more information
If you have any questions or comments about this advisory:
* Open an issue in [the Apollo Server repository](https://github.com/apollographql/apollo-server/)
* Email us at [security@apollographql.com](mailto:security@apollographql.com)

### Credits

This issue was discovered by Adrian Denkiewicz of [Doyensec](https://doyensec.com/research.html).

## Which versions are affected by GHSA-2fvv-qxrq-7jq6?

2 open source packages ship an affected version, including apollo-server-core.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `apollo-server-core` | npm | From 3.0.0 | 3.10.1 |
| `apollo-server-core` | npm | From 3.0.0 | 3.10.1 |

## How do I fix GHSA-2fvv-qxrq-7jq6?

Upgrade apollo-server-core to 3.10.1 or later.

## Is GHSA-2fvv-qxrq-7jq6 being exploited?

There is no known exploitation of GHSA-2fvv-qxrq-7jq6 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-2fvv-qxrq-7jq6 and fix it if it is affected.

What it is: GHSA-2fvv-qxrq-7jq6 is a cross-site scripting vulnerability in apollo-server-core, published on 18 Aug 2022. 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 GHSA-2fvv-qxrq-7jq6 in the wild and no public exploit code.

Affected packages and fixed versions:
- apollo-server-core (npm): affected from 3.0.0; fixed in 3.10.1
- apollo-server-core (npm): affected from 3.0.0; fixed in 3.10.1

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/GHSA-2fvv-qxrq-7jq6/ (Markdown: https://insights.sbomify.com/GHSA-2fvv-qxrq-7jq6/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-2fvv-qxrq-7jq6

---
From sbomify Insights: https://insights.sbomify.com/GHSA-2fvv-qxrq-7jq6/
Summaries are generated and may contain mistakes; the official description above is the record.