CVE-2026-41149

Description

Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Versions 10.9.5 and earlier, as well as 11.0.0-alpha.1 through 11.14.0, are vulnerable to HTML injection under the default configuration. Specifically, the classDef directive in Mermaid state diagrams permits DOM injection that escapes the SVG context. However, <script> tags are stripped, which prevents cross-site scripting (XSS). This issue has been fixed in versions 10.9.6 and 11.15.0. If developers are unable to immediately upgrade, they can work around this issue by setting "securityLevel": "sandbox", which prevents the issue by rendering the mermaid diagram in a sandboxed <iframe>.

How to fix CVE-2026-41149

To remediate CVE-2026-41149, upgrade the affected package to a fixed version below.

• —no fix listed
• —upgrade to 11.15.0 or later

Is CVE-2026-41149 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0
• >= 11.0.0-alpha.1, < 11.15.0

CVSS scores

References (9)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-41149
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2026-41149
• PATCHgithub.com/mermaid-js/mermaid
• WEBgithub.com/mermaid-js/mermaid/commit/37ff937f1da2e19f882fd1db01235db4d01f4056