CVE-2026-71436 Mermaid XY Charts are vulnerable to an infinite loop DoS
Attackers can cause a denial of service via infinite loop in Mermaid XY Charts by providing invalid X-Axis parameters, leading to memory exhaustion or crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-71436?
CVE-2026-71436 is a medium-severity denial of service vulnerability in mermaid-js mermaid, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. From version 10.6.0 until 10.9.8 and 11.16.1, Mermaid XY Charts are vulnerable to an infinite loop denial of service in the setXAxisRangeData function when configuring an X-Axis with invalid parameters. Because each loop iteration appends an element to an array, this generally causes a RangeError to appear after a few seconds, but it may instead cause the page or JavaScript process to crash from memory exhaustion, depending on the environment. This issue is fixed in versions 10.9.8 and 11.16.1.
Which versions are affected by CVE-2026-71436?
4 open source packages ship an affected version, including mermaid.
| Package | Affected | Fixed in |
|---|---|---|
mermaid npm | From 10.6.0 | 10.9.8 |
mermaid npm | From 10.6.0 | 10.9.8 |
mermaid npm | From 11.0.0-alpha.1 | 11.16.1 |
mermaid npm | From 11.0.0-alpha.1 | 11.16.1 |
How do I fix CVE-2026-71436?
Upgrade mermaid to a fixed version for your release line: 10.9.8 or 11.16.1.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-71436 being exploited?
There is no known exploitation of CVE-2026-71436 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-JY09186, DEBIAN-CVE-2026-71436, GHSA-2v8p-3f2j-5mp7, MINI-2xpf-w98h-85qm, MINI-4g38-44g9-chxf, MINI-669q-8q7p-gp8p and 2 more.