CVE-2025-59717 — @digitalocean/do-markdown…
MEDIUMCVE-2025-59717 is a medium-severity (CVSS 5.4) CWE-843 vulnerability in @digitalocean/do-markdownit. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.
@digitalocean/do-markdownit has Type Confusion vulnerability
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.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-59717.
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.
@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 |
Affected Products
do-markdownitdigitaloceanDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @digitalocean/do-markdownit, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
The records we use list no patched version of @digitalocean/do-markdownit for CVE-2025-59717. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
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.
Frequently Asked Questions
Is CVE-2025-59717 in your dependencies?
Find it across npm, including transitive dependencies.