GHSA-2h8j-8r9p-849f
MEDIUMGHSA-2h8j-8r9p-849f is a medium-severity (CVSS 5.4) CWE-843 vulnerability in @digitalocean/do-markdownit. O3 Security confirms whether GHSA-2h8j-8r9p-849f is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
@digitalocean/do-markdownit has Type Confusion vulnerability
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
@digitalocean/do-markdownitnpmDescription
Overview
A type confusion issue exists in the @digitalocean/do-markdownit package. In the callout and fence_environment plugins, the allowedClasses and allowedEnvironments options are expected to be arrays of strings. If these options are provided as a single string, the code applies .includes directly on the string, resulting in substring matching instead of membership checks against an array.
Affected Versions
All versions up to and including 1.16.1 (npm).
Impact
Supplying crafted input can bypass intended allow-lists (e.g., class/environment constraints) due to substring checks, which may enable rendering of unintended classes or environments and lead to policy bypass in downstream consumers.
Mitigation
Until an upstream fix is released, ensure configuration normalization before invoking the plugins:
- Validate that
allowedClassesandallowedEnvironmentsare arrays (Array.isArray(...)), converting single strings into one-element arrays when necessary. - Consider sanitizing or strictly validating user-controlled values that influence Markdown rendering.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @digitalocean/do-markdownit | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @digitalocean/do-markdownit. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of @digitalocean/do-markdownit has shipped for GHSA-2h8j-8r9p-849f yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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 pinpoints whether GHSA-2h8j-8r9p-849f is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-2h8j-8r9p-849f. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-2h8j-8r9p-849f in your dependencies?
O3 detects GHSA-2h8j-8r9p-849f across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.