Mermaid radar diagrams are vulnerable to DoS

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.3 · 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 · score source

EPSS

• CVE-2026-71439: 0.53% estimated exploitation activity in the next 30 days; percentile 44.74 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Mermaid radar diagrams allow arbitrary large values for ticks, which can cause high CPU usage, freezing the webpage/JavaScript process for long periods of time, until the process is eventually killed due to OOM/running out of memory. Proof-of-concept Patches Has the problem been patched? What versions should users upgrade to? This problem has been patched by https://github.com/mermaid-js/mermaid/commit/59b22fad2b3bb04f87a476c84a8a2b24679e607e, which was released in Mermaid v11.16.1 Workarounds Is there a way for users to fix or remediate the vulnerability without upgrading? There are no known workarounds without updating to a patched version of mermaid. References Are there any links users can visit to find out more? - https://github.com/mermaid-js/mermaid/commit/59b22fad2b3bb04f87a476c84a8a2b24679e607e - https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.16.1

Published by the source

6 Aug 2026, 20:01 UTC

Last modified by the source

6 Aug 2026, 20:01 UTC

Source last checked

26 Oct 2026, 13:00 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-rhh3-jpg6-66xh

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# Patch Next advisory brief: CVE-2026-71439

Advisory: Mermaid radar diagrams are vulnerable to DoS
IDs: CVE-2026-71439, GHSA-rhh3-jpg6-66xh
Record: https://patchnext.com/advisories/cve-2026-71439 (revision 1, source checked 26 Oct 2026, 13:00 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mermaid 11.16.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm mermaid: affected >= 11.6.0, < 11.16.1; fixed in 11.16.1

## Suggested inspection (read-only)
- `npm ls mermaid --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on mermaid.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-rhh3-jpg6-66xh (GitHub-reviewed advisory GHSA-rhh3-jpg6-66xh lists affected ranges: npm mermaid >=11.6.0 <11.16.1)

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