CVE-2025-54880: Mermaid Cross-Site Scripting Vulnerability

Q: What is CVE-2025-54880?

CVE-2025-54880 is a security vulnerability in Mermaid involving Mermaid does not properly sanitize architecture diagram iconText leading to XSS under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').

Q: Which Mermaid versions are affected?

Affected versions include releases prior to 11.10.0 across affected packages: mermaid.

Q: What version fixes CVE-2025-54880?

Upgrading to 11.10.0 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is mermaid affected?

Yes, mermaid is affected in releases prior to 11.10.0. Upgrade your dependency to 11.10.0 or later.

Q: What CWE is associated with CVE-2025-54880?

CVE-2025-54880 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).

Q: How can I check npm dependencies for CVE-2025-54880?

Run the dependency tree command: 'npm ls mermaid'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

MODERATE

Advisory Identifier: GHSA-8gwm-58g9-j8pw

CWE-79

Published 2025-08-19

Advisory Summary

CVE-2025-54880 is a MODERATE cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Mermaid libraries in the npm ecosystem. The issue involves mermaid does not properly sanitize architecture diagram icontext leading to xss. Remediation is available by upgrading affected packages to version 11.10.0.

CVE-2025-54880 at a Glance

CVE Identifier CVE-2025-54880

GHSA Identifier GHSA-8gwm-58g9-j8pw

Severity MODERATE

CVSS v3.1 Base Score N/A

CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected Product Mermaid

Package Ecosystem npm

Published Date 2025-08-19

Last Updated 2025-08-20

How to Fix CVE-2025-54880

To remediate this vulnerability, upgrade all affected Mermaid dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

mermaid fixed: 11.10.0

npm install mermaid@11.10.0

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

npm ls mermaid

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2025-54880, inspect your project dependencies using npm:

npm ls mermaid

Analyze the terminal output to locate any version of Mermaid in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 11.10.0), your application is affected.

Note: The npm ls mermaid command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Mermaid, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary In the default configuration of mermaid 11.9.0, user supplied input for architecture diagram icons is passed to the d3 `html()` method, creating a sink for cross site scripting. ### Details Architecture diagram service `iconText` values are passed to the d3 `html()` method, allowing malicious users to inject arbitrary HTML and cause XSS when mermaid-js is used in it's default configuration. The vulnerability lies here: ```ts export const drawServices = async function ( db: ArchitectureDB, elem: D3Element, services: ArchitectureService[] ): Promise<number> { for (const service of services) { /** ... **/ } else if (service.iconText) { bkgElem.html( `<g>${await getIconSVG('blank', { height: iconSize, width: iconSize, fallbackPrefix: architectureIcons.prefix })}</g>` ); const textElemContainer = bkgElem.append('g'); const fo = textElemContainer .append('foreignObject') .attr('width', iconSize) .attr('height', iconSize); const divElem = fo .append('div') .attr('class', 'node-icon-text') .attr('style', `height: ${iconSize}px;`) .append('div') .html(service.iconText); // <- iconText passed into innerHTML /** ... **/ }; }; ``` This issue was introduced with 734bde38777c9190a5a72e96421c83424442d4e4, around 15 months ago, which was released in [v11.1.0](https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.1.0). ### PoC Render the following diagram and observe the modified DOM. ``` architecture-beta group api(cloud)[API] service db "<img src=x onerror=\"document.write(`xss on ${document.domain}`)\">" [Database] in api ``` Here is a PoC on mermaid.live: https://mermaid.live/edit#pako:eNo9T8FOwzAM_ZXI4rBJpWrpRtuIISF24caZZdKyxOsiLUnlJjCo-u9kQ8wX-_n5-dkjKK8ROEhSRxNQhUh4v8cghWMpOvKxZ7I3M3XyUc83L-9v2z9qQPo0CpneMwFPxnZsILU6M--QyNNKCAHaq2jRhfyL0vLZ7jwMiWd3443Q3krjpt38Mv4sgG3WMsi9HHDLjLs4CwcZdGQ08EARM7BISZMgjJdLBIQjWhTAU6nxIOMpCBBuSrJeug_v7b8yPdMdgR_kaUgo9loGXBvZkbS3LqHTSK8-ugC8LMrrEuAjnIEvlnlVL9q6rZu6Lh-rRQbfwKuyyZuybcvqIaWiqKcMfq6uRd7Uy-kXhYFzcA ### Impact XSS on all sites that use mermaid and render user supplied diagrams without further sanitization. ### Remediation Sanitize the value of `iconText` before passing it to `html()`.

CVE-2025-54880 Affected Mermaid Versions

1 component(s)

Fixed Versions:

11.10.0

Product / Package	Ecosystem	Affected Versions	Fixed Version
mermaid npm/mermaid	npm	≥ 11.1.0 < 11.10.0	11.10.0

References

GitHub Advisory / Wiki ADVISORY

https://github.com/mermaid-js/mermaid/security/advisories/GHSA-8gwm-58g9-j8pw

NVD — CVE-2025-54880 NVD

https://nvd.nist.gov/vuln/detail/CVE-2025-54880

Security Fix Commit FIX COMMIT

https://github.com/mermaid-js/mermaid/commit/2aa83302795183ea5c65caec3da1edd6cb4791fc

Security Fix Commit FIX COMMIT

https://github.com/mermaid-js/mermaid/commit/734bde38777c9190a5a72e96421c83424442d4e4

Mermaid Source Repository REPOSITORY

https://github.com/mermaid-js/mermaid

Frequently Asked Questions

What is CVE-2025-54880?

CVE-2025-54880 is a security vulnerability in Mermaid involving Mermaid does not properly sanitize architecture diagram iconText leading to XSS under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').

Which Mermaid versions are affected?

Affected versions include releases prior to 11.10.0 across affected packages: mermaid.

What version fixes CVE-2025-54880?

Upgrading to 11.10.0 (or the latest patched release for your respective branch) resolves the vulnerability.

Is mermaid affected?

Yes, mermaid is affected in releases prior to 11.10.0. Upgrade your dependency to 11.10.0 or later.

What CWE is associated with CVE-2025-54880?

CVE-2025-54880 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).

How can I check npm dependencies for CVE-2025-54880?

Run the dependency tree command: 'npm ls mermaid'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

Machine-readable OSV JSON OSV v1.5 Schema

Normalized schema output

View Raw JSON

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8gwm-58g9-j8pw",
  "modified" : "2025-08-20T19:13:27Z",
  "published" : "2025-08-19T20:16:45Z",
  "aliases" : [ "CVE-2025-54880" ],
  "summary" : "Mermaid does not properly sanitize architecture diagram iconText leading to XSS",
  "details" : "### Summary\nIn the default configuration of mermaid 11.9.0, user supplied input for architecture diagram icons is passed to the d3 `html()` method, creating a sink for cross site scripting.\n\n### Details\nArchitecture diagram service `iconText` values are passed to the d3 `html()` method, allowing malicious users to inject arbitrary HTML and cause XSS when mermaid-js is used in it's default configuration. \n\nThe vulnerability lies here:\n\n```ts\nexport const drawServices = async function (\n  db: ArchitectureDB,\n  elem: D3Element,\n  services: ArchitectureService[]\n): Promise<number> {\n  for (const service of services) {\n    /** ... **/\n    } else if (service.iconText) {\n      bkgElem.html(\n        `<g>${await getIconSVG('blank', { height: iconSize, width: iconSize, fallbackPrefix: architectureIcons.prefix })}</g>`\n      );\n      const textElemContainer = bkgElem.append('g');\n      const fo = textElemContainer\n        .append('foreignObject')\n        .attr('width', iconSize)\n        .attr('height', iconSize);\n      const divElem = fo\n        .append('div')\n        .attr('class', 'node-icon-text')\n        .attr('style', `height: ${iconSize}px;`)\n        .append('div')\n        .html(service.iconText); // <- iconText passed into innerHTML\n       /** ... **/\n};\n};\n```\n\nThis issue was introduced with 734bde38777c9190a5a72e96421c83424442d4e4, around 15 months ago, which was released in [v11.1.0](https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.1.0).\n\n### PoC\nRender the following diagram and observe the modified DOM.\n\n```\narchitecture-beta\n    group api(cloud)[API]\n    service db \"<img src=x onerror=\\\"document.write(`xss on ${document.domain}`)\\\">\" [Database] in api\n```\n\nHere is a PoC on mermaid.live: https://mermaid.live/edit#pako:eNo9T8FOwzAM_ZXI4rBJpWrpRtuIISF24caZZdKyxOsiLUnlJjCo-u9kQ8wX-_n5-dkjKK8ROEhSRxNQhUh4v8cghWMpOvKxZ7I3M3XyUc83L-9v2z9qQPo0CpneMwFPxnZsILU6M--QyNNKCAHaq2jRhfyL0vLZ7jwMiWd3443Q3krjpt38Mv4sgG3WMsi9HHDLjLs4CwcZdGQ08EARM7BISZMgjJdLBIQjWhTAU6nxIOMpCBBuSrJeug_v7b8yPdMdgR_kaUgo9loGXBvZkbS3LqHTSK8-ugC8LMrrEuAjnIEvlnlVL9q6rZu6Lh-rRQbfwKuyyZuybcvqIaWiqKcMfq6uRd7Uy-kXhYFzcA\n\n### Impact\nXSS on all sites that use mermaid and render user supplied diagrams without further sanitization.\n\n### Remediation\nSanitize the value of `iconText` before passing it to `html()`.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "mermaid"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.1.0"
      }, {
        "fixed" : "11.10.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/mermaid-js/mermaid/security/advisories/GHSA-8gwm-58g9-j8pw"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-54880"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mermaid-js/mermaid/commit/2aa83302795183ea5c65caec3da1edd6cb4791fc"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mermaid-js/mermaid/commit/734bde38777c9190a5a72e96421c83424442d4e4"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mermaid-js/mermaid"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-08-19T20:16:45Z",
    "nvd_published_at" : "2025-08-19T17:15:41Z"
  }
}

CVSS V4

N/A MODERATE

Attack Vector N/A

Attack Complexity N/A

Privileges Required N/A

User Interaction N/A

Scope N/A

Confidentiality N/A

Integrity N/A

Availability N/A

Vector String

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Advisory Metadata

Source ID: GHSA-8gwm-58g9-j8pw
Schema Version: 1.4.0
Published: 2025-08-19 20:16
Last Modified: 2025-08-20 19:13
Database Record File: advisories/github-reviewed/2025/08/GHSA-8gwm-58g9-j8pw/GHSA-8gwm-58g9-j8pw.json