What’s Vulnerable › Vulnerabilities

CVE-2021-43861: Incorrect sanitisation function leads to `XSS`

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-12-30 · updated 2026-06-17
• Weakness: CWE-20

Description

Mermaid is a Javascript based diagramming and charting tool that uses Markdown-inspired text definitions and a renderer to create and modify complex diagrams. Prior to version 8.13.8, malicious diagrams can run javascript code at diagram readers' machines. Users should upgrade to version 8.13.8 to receive a patch. There are no known workarounds aside from upgrading.

Affected products

• mermaid-js mermaid: before 8.13.8 — fixed in 8.13.8

How to fix

Upgrade to a fixed version: mermaid-js mermaid 8.13.8. Check the vendor advisory for mitigations.

References

• https://github.com/mermaid-js/mermaid/commit/066b7a0d0bda274d94a2f2d21e4323dab5776d83
• https://github.com/mermaid-js/mermaid/releases/tag/8.13.8
• https://github.com/mermaid-js/mermaid/security/advisories/GHSA-p3rp-vmj9-gv6v
• https://github.com/mermaid-js/mermaid/commit/066b7a0d0bda274d94a2f2d21e4323dab5776d83
• https://github.com/mermaid-js/mermaid/releases/tag/8.13.8
• https://github.com/mermaid-js/mermaid/security/advisories/GHSA-p3rp-vmj9-gv6v

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