CVE-2026-41159

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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/mermaid-js/mermaid/commit/64769738d5b59211e1decb471ffbaca8afec51aa
https://github.com/mermaid-js/mermaid/commit/a9d9f0d8eb790349121508688cd338253fd80d76
https://github.com/mermaid-js/mermaid/releases/tag/mermaid@11.15.0	Release Notes
https://github.com/mermaid-js/mermaid/releases/tag/v10.9.6	Release Notes
https://github.com/mermaid-js/mermaid/security/advisories/GHSA-87f9-hvmw-gh4p	Third Party Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:mermaid_project:mermaid::::::node.js::*
	cpe:2.3:a:mermaid_project:mermaid::::::node.js::*

History

No history.

Information

Published : 2026-05-29 15:16

Updated : 2026-07-21 12:10

NVD link : CVE-2026-41159

Mitre link : CVE-2026-41159

CVE.ORG link : CVE-2026-41159

JSON object : View

Products Affected

mermaid_project

mermaid

CWE

CWE-94

Improper Control of Generation of Code ('Code Injection')

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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."}, {"lang": "es", "value": "Mermaid es una herramienta de JavaScript que utiliza texto inspirado en Markdown para crear y modificar diagramas y gr\u00e1ficos. 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