CVE-2026-71439 — mermaid
Fix: mermaid-js/mermaid@59b22faCVE-2026-71439 is a CWE-606 vulnerability in mermaid. A fix is available for mermaid — see the affected versions and patch details below.
Mermaid radar diagrams are vulnerable to DoS
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-71439.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
mermaidnpmDescription
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
radar-beta
axis a, b
curve c {1, 1}
ticks 1000000000
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?
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | mermaid | ≥ 11.6.0&&< 11.16.1 | 11.16.1npm install mermaid@11.16.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mermaid, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mermaid to 11.16.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-71439 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat ships Mermaid embedded in the same code-server based developer workbench images: OpenShift AI's odh-workbench-codeserver-datascience-cpu-py312 workbench image and OpenShift Dev Spaces' code-rhel9 image. The bundled version (>=11.6.0,<11.16.1) exposes users who render Mermaid Radar diagrams with excessively…
Avoid rendering untrusted Mermaid diagram content containing Radar diagrams with attacker-controlled 'ticks' parameters in the affected workbench images until the pinned mermaid dependency is upgraded to 11.16.1 or later.Source: Red Hat security advisory for CVE-2026-71439 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-71439 in your dependencies?
Find it across npm, including transitive dependencies.