CVE-2026-41149
Published:May 11, 2026
Updated:September 01, 2026
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>.
Affected Packages
mermaid (CDN_JS):
Affected version(s) >=0.1.0 <10.9.6Fix Suggestion:
Update to version 10.9.6mermaid (CDN_JS):
Affected version(s) >=11.0.0-alpha.1 <11.15.0Fix Suggestion:
Update to version 11.15.0https://github.com/mermaid-js/mermaid.git (GITHUB):
Affected version(s) >=v10.9.0 <v10.9.6Fix Suggestion:
Update to version v10.9.6https://github.com/mermaid-js/mermaid.git (GITHUB):
Affected version(s) >=mermaid@11.0.1 <mermaid@11.15.0Fix Suggestion:
Update to version mermaid@11.15.0mermaid (NPM):
Affected version(s) >=0.2.11 <10.9.6Fix Suggestion:
Update to version 10.9.6mermaid (NPM):
Affected version(s) >=11.0.0-alpha.1 <11.15.0Fix Suggestion:
Update to version 11.15.0Related Resources (7)
Do you need more information?
Contact UsCVSS v4
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
LOW
Subsequent System Integrity
LOW
Subsequent System Availability
LOW
CVSS v3
Base Score:
4.7
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Improper Control of Generation of Code ('Code Injection')
EPSS
Base Score:
0.40