# Apollo Server Core reflected XSS in default landing page

Source: https://junglewise.ai/threats/apollo-server-core-reflected-xss-in-default-landing-page-c61a38fd  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2022-08-18. Updated: 2026-05-14  
License: CC BY 4.0 with a link back

Severity: info · CVSS 4.3 · Published 2022-08-18

Apollo Server is a tool used to build GraphQL application interfaces. A security flaw in its default landing page could allow an attacker to execute malicious scripts in the web browsers of users visiting the server, specifically those using older browsers like Internet Explorer 11. This could lead to unauthorized actions being performed in the user's session or the theft of sensitive information if a user is tricked into clicking a malicious link.

Technologies: [apollo-server-core (npm)](https://junglewise.ai/threats/technologies/apollo-server-core). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** Informational severity, with a CVSS score of 4.3, published 18 August 2022.

**Which products and versions are affected?** apollo-server-core (npm) SEMVER:introduced=3.0.0,fixed=3.10.1.

**Is there a fix for This vulnerability?** Yes. apollo-server-core (npm): upgrade to 3.10.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is This vulnerability attacked?** It is attacked over the network, in a software library.

**Am I affected?** Check whether you run apollo-server-core (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- apollo-server-core (npm): upgrade to 3.10.1 or later

  ```sh
  npm install apollo-server-core@3.10.1
  ```


## Technical details

A reflected Cross-Site Scripting (XSS) vulnerability exists in apollo-server-core versions 3.0.0 through 3.10.0. The vulnerability is located in the default landing page, which interpolates the server's URL from 'window.location.href' into a sample curl command. In older browsers such as Internet Explorer 11, this value is not automatically URI-encoded, allowing an attacker to craft a URL containing malicious JavaScript. If a user using an affected browser visits the malicious link and the landing page bundle fails to load from the CDN, the script will execute in the context of the user's session. The issue is fixed in version 3.10.1 by removing the sample curl command from the landing page.

## Affected products

- Apollo GraphQL apollo-server-core >= 3.0.0, < 3.10.1

## Timeline

- 2022-08-10: advisory: Original GitHub security advisory published
- 2022-08-18: disclosed: Public disclosure via OSV/GHSA database

## References

- [https://github.com/apollographql/apollo-server/security/advisories/GHSA-2fvv-qxrq-7jq6](https://github.com/apollographql/apollo-server/security/advisories/GHSA-2fvv-qxrq-7jq6)
- [https://github.com/apollographql/apollo-server/commit/68a439b6e3af9edc8a2480092f2d49f058be1e64](https://github.com/apollographql/apollo-server/commit/68a439b6e3af9edc8a2480092f2d49f058be1e64)
- [https://github.com/apollographql/apollo-server](https://github.com/apollographql/apollo-server)

## Related threats

- [Apollo Server XS-Search bypass via browser CORS bug](https://junglewise.ai/threats/apollo-server-xs-search-bypass-via-browser-cors-bug-108494ad)
- [Apollo Server sensitive information exposure in logging](https://junglewise.ai/threats/apollo-server-sensitive-information-exposure-in-logging-64cb113a)
- [Apollo Server incorrect cache-control header in batched requests](https://junglewise.ai/threats/apollo-server-incorrect-cache-control-header-in-batched-requests-d59ff0b9)
- [Apollo Server schema validation bypass on WebSocket subscriptions](https://junglewise.ai/threats/apollo-server-schema-validation-bypass-on-websocket-subscriptions-f355648d)