CVE-2026-71437 — Mermaid Architecture diagrams are vulnerable to prototype pollution
Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. From version 11.5.0 until 11.16.1, Mermaid Architecture Diagrams are vuln…
Published: 2026-08-06 · CVSS: 6.5 · CVSS 4.0
Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. From version 11.5.0 until 11.16.1, Mermaid Architecture Diagrams are vulnerable to prototype pollution when a diagram defines a group with an id of __proto__. Because the group id is used directly as an object property key without validation, an attacker who can supply diagram text can pollute Object.prototype, potentially affecting the behavior of the embedding application. This issue is fixed in version 11.16.1.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7