CVE-2025-54881: Mermaid-Js Mermaid

Medium severity, CVSS 5.3. EPSS: 0.8% chance of exploitation in the next 30 days.

Mermaid is a JavaScript based diagramming and charting tool that uses Markdown-inspired text definitions and a renderer to create and modify complex diagrams. In the default configuration of mermaid 10.9.0-rc.1 to 11.9.0, user supplied input for sequence diagram labels is passed to innerHTML during calculation of element size, causing XSS.

Affected products

• Mermaid-Js Mermaid: from 10.9.0-rc.1, up to and including 11.9.0

Published 2025-08-19. Last modified 2026-06-17.