CVE-2025-59717: Digitalocean Do-Markdownit

Critical severity, CVSS 9.8. EPSS: 0.4% chance of exploitation in the next 30 days.

In the @digitalocean/do-markdownit package through 1.16.1 (in npm), the callout and fence_environment plugins perform .includes substring matching if allowedClasses or allowedEnvironments is a string (instead of an array).

Affected products

• Digitalocean Do-Markdownit: up to and including 1.16.1

Published 2025-09-19. Last modified 2026-06-17.