CVE-2026-41150: Mermaid Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-6m6c-36f7-fhxh
Share
CVSS 5.3
CWE-835
Published
Advisory Summary

CVE-2026-41150 is a MODERATE (CVSS 5.3) denial of service vulnerability (CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')) affecting Mermaid libraries in the npm ecosystem. The issue involves mermaid gantt charts are vulnerable to an infinite loop dos. Remediation is available by upgrading affected packages to version 11.15.0, 10.9.6.

CVE-2026-41150 at a Glance

CVE Identifier CVE-2026-41150
GHSA Identifier GHSA-6m6c-36f7-fhxh
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
Affected Product Mermaid
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability Low (A:L)

How to Fix CVE-2026-41150

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: 11.15.0 
npm install mermaid@11.15.0
mermaid fixed: 10.9.6 
npm install mermaid@10.9.6
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-2026-41150, 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 11.15.0), 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-835: Loop with Unreachable Exit Condition ('Infinite Loop'), where the product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. 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

### Impact Mermaid v11.14.0 and earlier are vulnerable to a denial-of-service attack when rendering gantt charts, if they use the [`excludes` attribute](https://mermaid.js.org/syntax/gantt.html?#excludes) to exclude all dates. Example: ``` gantt excludes monday,tuesday,wednesday,thursday,friday,saturday,sunday DoS :2025-01-01, 1d ``` `mermaid.parse` is unaffected, unless you then call the `ganttDb.getTasks()` (which is called when rendering a diagram). ### Patches This has been patched in: - [v11.15.0](https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.15.0) (see [faafb5d49106dd32c367f3882505f2dd625aa30e](https://github.com/mermaid-js/mermaid/commit/faafb5d49106dd32c367f3882505f2dd625aa30e)) - [v10.9.6](https://github.com/mermaid-js/mermaid/releases/tag/v10.9.6) (see [a59ea56174712ee5430dfd5bc877cb5151f501a6](https://github.com/mermaid-js/mermaid/commit/a59ea56174712ee5430dfd5bc877cb5151f501a6)) ### Workarounds There are no workarounds available without updating to a newer version of mermaid.

CVE-2026-41150 Affected Mermaid Versions

2 component(s)
Fixed Versions:
11.15.010.9.6
Product / Package Ecosystem Affected Versions Fixed Version
mermaid
npm/mermaid
npm
≥ 11.0.0-alpha.1
< 11.15.0
11.15.0
mermaid
npm/mermaid
npm
< 10.9.6
10.9.6

References

GitHub Advisory / Wiki ADVISORY
https://github.com/mermaid-js/mermaid/security/advisories/GHSA-6m6c-36f7-fhxh
NVD — CVE-2026-41150 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-41150
Security Fix Commit FIX COMMIT
https://github.com/mermaid-js/mermaid/commit/a59ea56174712ee5430dfd5bc877cb5151f501a6
Security Fix Commit FIX COMMIT
https://github.com/mermaid-js/mermaid/commit/faafb5d49106dd32c367f3882505f2dd625aa30e
Mermaid Source Repository REPOSITORY
https://github.com/mermaid-js/mermaid
Mermaid Release RELEASE
https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.15.0
Mermaid Release RELEASE
https://github.com/mermaid-js/mermaid/releases/tag/v10.9.6

Frequently Asked Questions

What is CVE-2026-41150?
CVE-2026-41150 is a security vulnerability in Mermaid involving Mermaid Gantt Charts are vulnerable to an Infinite Loop DoS under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop').
Which Mermaid versions are affected?
Affected versions include releases prior to 11.15.0, 10.9.6 across affected packages: mermaid.
What version fixes CVE-2026-41150?
Upgrading to 11.15.0, 10.9.6 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mermaid affected?
Yes, mermaid is affected in releases prior to 11.15.0, 10.9.6. Upgrade your dependency to 11.15.0, 10.9.6 or later.
What is the CVSS score of CVE-2026-41150?
CVE-2026-41150 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2026-41150?
CVE-2026-41150 is classified under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') (The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.).
How can I check npm dependencies for CVE-2026-41150?
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-6m6c-36f7-fhxh",
  "modified" : "2026-06-09T10:28:48Z",
  "published" : "2026-05-11T19:36:55Z",
  "aliases" : [ "CVE-2026-41150" ],
  "summary" : "Mermaid Gantt Charts are vulnerable to an Infinite Loop DoS",
  "details" : "### Impact\n\nMermaid v11.14.0 and earlier are vulnerable to a denial-of-service attack when rendering gantt charts, if they use the [`excludes` attribute](https://mermaid.js.org/syntax/gantt.html?#excludes) to exclude all dates.\n\nExample:\n\n```\ngantt\n  excludes monday,tuesday,wednesday,thursday,friday,saturday,sunday\n  DoS :2025-01-01, 1d\n```\n\n`mermaid.parse` is unaffected, unless you then call the `ganttDb.getTasks()` (which is called when rendering a diagram).\n\n### Patches\n\nThis has been patched in:\n\n- [v11.15.0](https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.15.0) (see [faafb5d49106dd32c367f3882505f2dd625aa30e](https://github.com/mermaid-js/mermaid/commit/faafb5d49106dd32c367f3882505f2dd625aa30e))\n- [v10.9.6](https://github.com/mermaid-js/mermaid/releases/tag/v10.9.6) (see [a59ea56174712ee5430dfd5bc877cb5151f501a6](https://github.com/mermaid-js/mermaid/commit/a59ea56174712ee5430dfd5bc877cb5151f501a6))\n\n### Workarounds\n\nThere are no workarounds available without updating to a newer version of mermaid.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "mermaid"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.0.0-alpha.1"
      }, {
        "fixed" : "11.15.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 11.14.0"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "mermaid"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "10.9.6"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 10.9.5"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/mermaid-js/mermaid/security/advisories/GHSA-6m6c-36f7-fhxh"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-41150"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mermaid-js/mermaid/commit/a59ea56174712ee5430dfd5bc877cb5151f501a6"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mermaid-js/mermaid/commit/faafb5d49106dd32c367f3882505f2dd625aa30e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mermaid-js/mermaid"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.15.0"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mermaid-js/mermaid/releases/tag/v10.9.6"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-835" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-11T19:36:55Z",
    "nvd_published_at" : "2026-05-29T15:16:22Z"
  }
}