CVE-2026-41159 : faille moyenne mermaid project mermaid (CVSS 5.3)

Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Prior to 10.9.6 and 11.15.0, Mermaid's default configuration allows injecting CSS that applies outside of the Mermaid diagram via the fontFamily, themeCSS, and altFontFamily configuration options. The injected CSS exploits stylis's & (scope reference) handling. :not(&) escapes the #mermaid-xxx automatic scoping, applying styles to all page elements. Global at-rules (@font-face, @keyframes, @counter-style) are also injectable as stylis hoists them to top level. This allows page defacement and DOM attribute exfiltration via CSS :has() selectors. This vulnerability is fixed in 10.9.6 and 11.15.0.

Sévérité

Moyenne (CVSS 5.3)

Vecteur CVSS

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploitation active

Non signalée par la CISA

Publication

29 mai 2026

Dernière mise à jour

21 juil. 2026

• mermaid project mermaid

• Fiche CVE-2026-41159 sur le NVD (NIST)
• github.com/mermaid…
• github.com/mermaid…
• github.com/mermaid-js/mermaid/releases/tag/mermaid@11.15.0
• github.com/mermaid-js/mermaid/releases/tag/v10.9.6
• github.com/mermaid…