Mermaid before 8.11.0 allows XSS when the antiscript feature is used.
Priority LOW 29CWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-79.
Summary
Mermaid before 8.11.0 allows XSS when the antiscript feature is used.
Why it matters now
EPSS 0.01018 63rd percentileScored 2026-11-07
Fix Fixed mermaid (npm): 8.11.0
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
| — | mermaid (npm) | before 8.11.0 | 8.11.0 | Patch available | GHSA-4f6x-49g2-99fm |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
- mermaid (npm) Vendor— Affected before 8.11.0 Fixed in 8.11.0 Patch available GHSA-4f6x-49g2-99fm
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mermaid_project:mermaid:*:*:*:*:*:node.js:*:* | before 8.11.0 | Vulnerable | mermaid-js |
- cpe:2.3:a:mermaid_project:mermaid:*:*:*:*:*:node.js:*:* Versions before 8.11.0 Vulnerable ·mermaid-js
Remediation
- Fix · GHSA-4f6x-49g2-99fm mermaid (npm) Fixed in 8.11.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2021-35513
- 2026-10-03 Alias added: GHSA-4f6x-49g2-99fm
References
Advisory 3
More mermaid-js Mermaid vulnerabilities
- TI-2026-29778 Mermaid Gantt Charts are vulnerable to an Infinite Loop DoS CVSS 4.0MEDIUM 5.3
- TI-2022-13152 Arbitrary `CSS` injection into the generated graph affecting the container HTML in mermaid.js CVSS 3.1MEDIUM 6.1
- TI-2025-34614 Mermaid does not properly sanitize architecture diagram iconText leading to XSS CVSS 4.0MEDIUM 5.1
- TI-2021-19667 Incorrect sanitisation function leads to `XSS` CVSS 3.1HIGH 7.2
- TI-2026-29785 Mermaid: Improper sanitization of configuration leads to CSS injection CVSS 4.0MEDIUM 5.3
Sources
- CVE-2021-35513 · CVE Program
- CVE-2021-35513 · NVD
- FIRST EPSS
- GHSA-4f6x-49g2-99fm · GitHub Advisory Database · CC BY 4.0
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