Summary
Mermaid radar diagrams are vulnerable to DoS
Proof-of-concept
radar-beta
axis a, b
curve c {1, 1}
ticks 1000000000
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?
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.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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
Frequently Asked Questions
- What is CVE-2026-71439? CVE-2026-71439 is a medium-severity security vulnerability in mermaid (npm), affecting versions >= 11.6.0, < 11.16.1. It is fixed in 11.16.1.
- Which versions of mermaid are affected by CVE-2026-71439? mermaid (npm) versions >= 11.6.0, < 11.16.1 is affected.
- Is there a fix for CVE-2026-71439? Yes. CVE-2026-71439 is fixed in 11.16.1. Upgrade to this version or later.
- Is CVE-2026-71439 exploitable, and should I be worried? Whether CVE-2026-71439 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-71439 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-71439? Upgrade
mermaidto 11.16.1 or later.