CVE-2022-25863 is a high-severity (CVSS 8.1) Deserialization of Untrusted Data vulnerability in gatsby-plugin-mdx. 3 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for gatsby-plugin-mdx — see the affected versions and patch details below.
Deserialization of Untrusted Data
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
gatsby-plugin-mdxnpmDescription
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 [email protected] and [email protected] 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 [email protected].
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | gatsby-plugin-mdx | all versions | 2.14.1npm install gatsby-plugin-mdx@2.14.1 |
| 📦npm | gatsby-plugin-mdx | ≥ 3.0.0&&< 3.15.2 | 3.15.2npm install gatsby-plugin-mdx@3.15.2 |
Affected Products
gatsby-plugin-mdxgatsbyjsResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gatsby-plugin-mdx, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update gatsby-plugin-mdx to 2.14.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-25863 is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.
Frequently Asked Questions
Is CVE-2022-25863 in your dependencies?
Find it across npm, including transitive dependencies.