CVE-2023-22491 — gatsby-transformer-remark
HIGHCVE-2023-22491 is a high-severity (CVSS 8.1) Improper Input Validation vulnerability in gatsby-transformer-remark. 1 public exploit reference exists, so weaponization risk is real. A fix is available for gatsby-transformer-remark — see the affected versions and patch details below.
gatsby-transformer-remark vulnerable to unsanitized JavaScript code injection
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-22491.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-22491 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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-transformer-remarknpmDescription
Impact
The gatsby-transformer-remark plugin prior to versions 5.25.1 and 6.3.2 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 in gatsby-transformer-remark when passing input in data mode (querying MarkdownRemark 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 by or added into a file processed by gatsby-transformer-remark. The following 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 MarkdownRemark input is attempting to use the Frontmatter engine.
Workarounds
If an older version of gatsby-transformer-remark 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.
For more information
Email us at [email protected].
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | gatsby-transformer-remark | ≥ 6.0.0&&< 6.3.2 | 6.3.2npm install gatsby-transformer-remark@6.3.2 |
| 📦npm | gatsby-transformer-remark | all versions | 5.25.1npm install gatsby-transformer-remark@5.25.1 |
Research 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-transformer-remark, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update gatsby-transformer-remark to 6.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-22491 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-22491 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-22491. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-22491 in your dependencies?
O3 Security finds CVE-2023-22491 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.