External risk intelligence

Gatsby Plugin MDX Untrusted Data Deserialization

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2022-25863

This vulnerability exists in a build-time plugin for Gatsby, a static site generator. The affected code processes files during the development or build phase to generate static assets, not within the runtime environment of the deployed website. Consequently, there is no public-facing network service or internet-reachable attack surface associated with this plugin.

Deserialization

Gatsbyjs Gatsby Plugin Mdx

before 2.14.13.0.0 to before 3.15.2

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A security issue has been identified in a component used within the Gatsby development framework, specifically affecting how certain data is processed. This vulnerability could allow for the unauthorized modification or disclosure of information if an attacker can provide malicious input during the build process. The main concern is to confirm if this component is in use and to what extent it might be exposed.

Untrusted data processing flaw in a Gatsby development tool.
Critical risk if exploitable, requires confirming relevance.
Assess exposure of the Gatsby build process to untrusted input.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by sending specially crafted input to a Gatsby website that uses the `gatsby-plugin-mdx`. This input could be processed during the site's build or development phase, potentially leading to the execution of arbitrary code. This could occur when MDX files are used in the `src/pages` directory or imported as components in React code, or when querying MDX data through GraphQL.

Entry condition: Unsanitized input processed by plugin.
Trigger point: Passing input through gray-matter package.
Resulting risk: Arbitrary code execution.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could impact the integrity and availability of data processed by `gatsby-plugin-mdx` when handling untrusted input. When MDX files are processed during the build phase, either through webpack or in data mode via GraphQL, improperly sanitized input could lead to unexpected behavior or data corruption.

Build-time data processing could be affected.
Untrusted input may be deserialized without sanitization.
Potential for data corruption or unexpected service behavior.

Operational Fix

Recommended remediation, mitigation, and detection steps

For this vulnerability in `gatsby-plugin-mdx`, the application owners responsible for Gatsby sites and the platform or infrastructure teams managing the build environments are likely to be involved. The first practical step is to identify all Gatsby sites and projects, confirm which ones use the affected plugin, and then prioritize remediation based on the criticality of the sites and the potential for exploit during the build process.

Application and platform teams own remediation.
Verify all Gatsby projects and plugin usage.
Plan build environment updates and testing.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is gatsby-plugin-mdx and how is it used?

Gatsby-plugin-mdx is a component for the Gatsby framework that enables developers to use MDX—a format combining Markdown and JSX—within their web projects. It allows sites to render complex React components directly inside Markdown files, facilitating the creation of content-driven websites. Developers rely on this tool to build, process, and bundle site content into static assets during the project's development or build phase.

What does deserialization of untrusted data mean for CVE-2022-25863?

This vulnerability is classified as CWE-502, Deserialization of Untrusted Data. It occurs because the plugin passes input to the gray-matter package without sufficient sanitization. In plain terms, the software blindly trusts and processes specially crafted data files, which can trick the system into executing unintended commands or code when it attempts to interpret that data during the build process.

How can an attacker trigger this vulnerability?

An attacker triggers the flaw by providing malicious, unsanitized input that the plugin subsequently processes. This happens when the plugin handles MDX files within the source code or processes MDX data via GraphQL queries. Importantly, simply visiting the final, static version of a website does not trigger this issue, as the vulnerability is tied to the internal data-processing steps that occur before the site is ever deployed.

Is my website at risk according to Halo Surface Signal?

Halo Surface Signal indicates that exploitation is very unlikely because this plugin operates exclusively during the build or development phase. It is not an active service running on your live website. Since the code only executes to generate static files and does not function as an internet-facing network service, it lacks the typical remote attack surface found in standard runtime web vulnerabilities.

What are the first steps to address this Gatsby plugin issue?

Start by auditing your codebase to determine if you are using an affected version of gatsby-plugin-mdx. If you identify an vulnerable version, the recommended path is to update to a patched release. If an immediate update is not feasible, you must implement strict sanitization for all input passed into the plugin to ensure that no malicious data reaches the underlying processing logic.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.