CVE-2026-50159
Published:August 06, 2026
Updated:August 18, 2026
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.
Affected Packages
mermaid (CDN_JS):
Affected version(s) >=0.1.0 <10.9.8Fix Suggestion:
Update to version 10.9.8mermaid (CDN_JS):
Affected version(s) >=11.0.0-alpha.1 <11.16.1Fix Suggestion:
Update to version 11.16.1mermaid (CDN_JS):
Affected version(s) >=0.1.0 <10.9.8Fix Suggestion:
Update to version 10.9.8https://github.com/mermaid-js/mermaid.git (GITHUB):
Affected version(s) >=mermaid@11.0.1 <mermaid@11.16.1Fix Suggestion:
Update to version mermaid@11.16.1https://github.com/mermaid-js/mermaid.git (GITHUB):
Affected version(s) >=v8.8.4 <v10.9.8Fix Suggestion:
Update to version v10.9.8mermaid (NPM):
Affected version(s) >=0.2.11 <10.9.8Fix Suggestion:
Update to version 10.9.8mermaid (NPM):
Affected version(s) >=11.0.0-alpha.1 <11.16.1Fix Suggestion:
Update to version 11.16.1mermaid (NPM):
Affected version(s) >=0.2.11 <10.9.8Fix Suggestion:
Update to version 10.9.8Related Resources (9)
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:
0.57