Medium

Mermaid Gantt Charts are vulnerable to an Infinite Loop DoS

  • Disclosed: 11.05.2026
  • Updated: 11.10.2026 10:22

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 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:

Workarounds

There are no workarounds available without updating to a newer version of mermaid.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package mermaid >= 11.0.0-alpha.1, < 11.15.0, < 10.9.6 11.15.0, 10.9.6

References

CVSS score 5.3/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE)
CWE-835
Platform
npm
Package
mermaid
Disclosed
11.05.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-6m6c-36f7-fhxh - CC BY 4.0

Vulnerability history: mermaid

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (16) in the archive
Total entries
16
First → latest
09.2020 08.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 3
  • Medium 12
  • Low 1

Disclosures per year

  1. 2020: 1
  2. 2021: 1
  3. 2022: 2
  4. 2023: 0
  5. 2024: 1
  6. 2025: 2
  7. 2026: 9
Severity:
  1. Mermaid Gantt Charts are vulnerable to an Infinite Loop DoS this entry
    Medium · 5.3 CVE-2026-41150 >= 11.0.0-alpha.1, < 11.15.0, < 10.9.6 11.15.0, 10.9.6
  2. High · 7.2 CVE-2021-43861 < 8.13.8 8.13.8
  3. High ghsa-w32g-5hqp-gg6q < 8.2.3 8.2.3

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