Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Prior to 10.9.8 and 11.16.1, Mermaid is vulnerable to CSS injection via sibling combinator selectors generated from diagram-supplied class or id names. An attacker who can supply diagram text can inject arbitrary CSS into the rendered page, potentially altering the appearance or behavior of unrelated page elements. This issue is fixed in versions 10.9.8 and 11.16.1.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-6x64-9x62-f2gx Mermaid allows CSS injection applying to sibling elements of the diagram
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 07 Aug 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 07 Aug 2026 09:15:00 +0000

Type Values Removed Values Added
First Time appeared Mermaid Project
Mermaid Project mermaid
Vendors & Products Mermaid Project
Mermaid Project mermaid

Thu, 06 Aug 2026 22:15:00 +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 10.9.8 and 11.16.1, Mermaid is vulnerable to CSS injection via sibling combinator selectors generated from diagram-supplied class or id names. An attacker who can supply diagram text can inject arbitrary CSS into the rendered page, potentially altering the appearance or behavior of unrelated page elements. This issue is fixed in versions 10.9.8 and 11.16.1.
Title Mermaid allows CSS injection applying to sibling elements of the diagram
Weaknesses CWE-94
References
Metrics cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-07T17:18:23.685Z

Reserved: 2026-06-03T20:54:20.432Z

Link: CVE-2026-50159

cve-icon Vulnrichment

Updated: 2026-08-07T17:18:10.914Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-07T09:00:05Z

Weaknesses