CVE-2025-59717 — @digitalocean/do-markdown…
MEDIUMCVE-2025-59717 is a medium-severity (CVSS 5.4) CWE-843 vulnerability in @digitalocean/do-markdownit. No vendor fix is recorded yet; mitigation options are listed below.
@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
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-2025-59717 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.
@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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of @digitalocean/do-markdownit has shipped for CVE-2025-59717 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-59717 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-59717. 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-2025-59717 in your dependencies?
O3 Security finds CVE-2025-59717 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.