CVE-2026-71437
Mermaid Architecture diagrams are vulnerable to prototype pollution
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. From version 11.5.0 until 11.16.1, Mermaid Architecture Diagrams are vulnerable to prototype pollution when a diagram defines a group with an id of __proto__. Because the group id is used directly as an object property key without validation, an attacker who can supply diagram text can pollute Object.prototype, potentially affecting the behavior of the embedding application. This issue is fixed in version 11.16.1.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | Medium6.5 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:H/SI:H/SA:H |
| NVDNVD · Awaiting Analysis | 4.0 | Medium6.5 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.50% · top 57% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Weakness
Affected products
- affected >= 11.5.0, < 11.16.1
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- npmmermaidGHSA-3rrr-jr9j-h3q3 (opens in a new tab)
References (4)
- https://github.com/mermaid-js/mermaid/security/advisories/GHSA-3rrr-jr9j-h3q3 (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/mermaid-js/mermaid/pull/8022 (opens in a new tab)x_refsource_MISC
- https://github.com/mermaid-js/mermaid/commit/99af3fc35ef0a9a9c8c6314521344d67523ddccf (opens in a new tab)x_refsource_MISC
- https://github.com/mermaid-js/mermaid/releases/tag/[email protected] (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-3rrr-jr9j-h3q3 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-71437)Record last updated .