CVE-2026-71438
CVE-2026-71438 · Mermaid configuration APIs allow prototype pollution
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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's configuration setters (mermaid.initialize, mermaidAPI.setConfig, and mermaidAPI.updateSiteConfig) merge caller-supplied configuration into Mermaid's internal config using the assignWithDepth deep-merge helper, which is vulnerable to prototype pollution. This is only exploitable if an application forwards untrusted data directly into one of these configuration entry points, which is outside their documented usage; diagram-supplied configuration (e.g. %%{init: {}}%% or YAML frontmatter) is not affected. This issue is fixed in versions 10.9.8 and 11.16.1.
CVSS 2.4 · Low · EPSS 0.4% · Fix available
- Published
- Updated
Affected products and versions
mermaid
- Versions
- < 10.9.8: Affected
- >= 11.0.0-alpha.1, < 11.16.1: Affected
No fix published
node-mermaid Debian:14
- Versions
- 8.11.0+ds+~cs29.13.22-1
- 8.13.2+ds+~cs30.13.21-1
- 8.13.2+ds+~cs30.13.21-1.1
- 8.13.3+ds+~cs26.13.21-1
- 8.13.3+ds+~cs26.13.21-2
- 8.13.8+~cs10.4.16-1
- 8.14.0+ds1+~cs11.4.14-1
- 8.14.0+~cs11.4.14-1
- 8.7.0+ds+~cs27.17.17-1
- 8.7.0+ds+~cs27.17.17-2
- 8.7.0+ds+~cs27.17.17-2~bpo10+1
- 8.7.0+ds+~cs27.17.17-3
- 8.9.1+ds+~cs26.20.25-1
- 8.9.3+ds+~cs29.13.19-1
- 9.2.2+~2.0.0-1
- 9.2.2+~2.0.0-2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
mermaid npm
- Affected ranges
- SEMVER: ≥ 11.0.0-alpha.1, < 11.16.1
Update to 11.16.1
mermaid npm
- Affected ranges
- SEMVER: < 10.9.8
Update to 10.9.8
node-mermaid Ubuntu:22.04:LTS
- Versions
- 8.7.0+ds+~cs27.17.17-3
- 8.13.3+ds+~cs26.13.21-1
- 8.13.3+ds+~cs26.13.21-2
- 8.13.8+~cs10.4.16-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
node-mermaid Ubuntu:26.10
- Versions
- 9.2.2+~2.0.0-1
- 9.2.2+~2.0.0-2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
Original sources
- https://github.com/mermaid-js/mermaid/security/advisories/GHSA-c4c3-pg64-4m4v
- https://github.com/mermaid-js/mermaid/pull/8022
- https://github.com/mermaid-js/mermaid/commit/2cd6dcf735533b323507e3e889ffdea870540b43
- https://github.com/mermaid-js/mermaid/commit/c34b07a0815842327e70794d69b0c8c5a1e2a956
- https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.16.1
- https://github.com/mermaid-js/mermaid/releases/tag/v10.9.8
- https://nvd.nist.gov/vuln/detail/CVE-2026-71438