Package Instance

Gatsby develop server has Local File Inclusion vulnerability
### Impact

The Gatsby framework prior to versions 4.25.7 and 5.9.1 contain a Local File Inclusion vulnerability in the `__file-code-frame` and `__original-stack-frame` paths, exposed when running the Gatsby develop server (`gatsby develop`).

The following steps can be used to reproduce the vulnerability:

```
# Create a new Gatsby project
$ npm init gatsby
$ cd my-gatsby-site

# Start the Gatsby develop server
$ gatsby develop

# Execute the Local File Inclusion vulnerability in __file-code-frame
$ curl "http://127.0.0.1:8000/__file-code-frame?filePath=/etc/passwd&lineNumber=1"

# Execute the Local File Inclusion vulnerability in __original-stack-frame
$ curl "http://127.0.0.1:8000/__original-stack-frame?moduleId=/etc/hosts&lineNumber=1&skipSourceMap=1"
```

It should be noted that by default `gatsby develop` is only accessible via the localhost `127.0.0.1`, and one would need to intentionally expose the server to other interfaces to exploit this vulnerability by using server options such as `--host 0.0.0.0`, `-H 0.0.0.0`, or the `GATSBY_HOST=0.0.0.0` environment variable.


### Patches

A patch has been introduced in `gatsby@5.9.1` and `gatsby@4.25.7` which mitigates the issue.


### Workarounds

As stated above, by default `gatsby develop` is only exposed to the localhost `127.0.0.1`.  For those using the develop server in the default configuration no risk is posed.  If other ranges are required, preventing the develop server from being exposed to untrusted interfaces or IP address ranges would mitigate the risk from this vulnerability.

We encourage projects to upgrade to the latest major release branch for all Gatsby plugins to ensure the latest security updates and bug fixes are received in a timely manner.


### Credits

We would like to thank Maxwell Garrett of Assetnote for bringing the `__file-code-frame` issue to our attention.


### For more information

Email us at [security@gatsbyjs.com](mailto:security@gatsbyjs.com).

Unsanitized JavaScript code injection possible in gatsby-plugin-mdx
### Impact
The gatsby-plugin-mdx plugin prior to versions 3.15.2 and 2.14.1 passes input through to the `gray-matter` npm package, which is vulnerable to JavaScript injection in its default configuration, unless input is sanitized.  The vulnerability is present when passing input in both webpack (MDX files in `src/pages` or MDX file imported as component in frontend / React code) and data mode (querying MDX nodes via GraphQL).  Injected JavaScript executes in the context of the build server.

To exploit this vulnerability untrusted/unsanitized input would need to be sourced or added into an MDX file.  The following MDX payload demonstrates a vulnerable configuration:
```
---js
((require("child_process")).execSync("id >> /tmp/rce"))
--- 
```

### Patches
A patch has been introduced in `gatsby-plugin-mdx@3.15.2` and `gatsby-plugin-mdx@2.14.1` which mitigates the issue by disabling the `gray-matter` JavaScript Frontmatter engine.  The patch introduces a new option, `JSFrontmatterEngine` which is set to `false` by default.  When setting `JSFrontmatterEngine` to `true`, input passed to `gatsby-plugin-mdx` must be sanitized before processing to avoid a security risk.  Warnings are displayed when enabling `JSFrontmatterEngine` to `true` or if it appears that the MDX input is attempting to use the Frontmatter engine.

### Workarounds
If an older version of `gatsby-plugin-mdx` must be used, input passed into the plugin should be sanitized ahead of processing.

**We encourage projects to upgrade to the latest major release branch for all Gatsby plugins to ensure the latest security updates and bug fixes are received in a timely manner.**

### Credits
We would like to thank Snyk [snyk.io] for initially bringing the issue to our attention, as well as Feng Xiao and Zhongfu Su, who reported the issue to Snyk.

### For more information
Email us at [security@gatsbyjs.com](mailto:security@gatsbyjs.com).