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.
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History
Fri, 29 May 2026 14:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | Mermaid: Improper sanitization of configuration leads to CSS injection | |
| Weaknesses | CWE-94 | |
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cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-05-29T15:02:56.459Z
Reserved: 2026-04-17T16:34:45.524Z
Link: CVE-2026-41159
No data.
Status : Awaiting Analysis
Published: 2026-05-29T15:16:22.813
Modified: 2026-05-29T16:25:57.843
Link: CVE-2026-41159
No data.
OpenCVE Enrichment
Updated: 2026-05-29T15:45:16Z