Is CVE-2026-71436 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-71436 being exploited in the wild.

How severe is CVE-2026-71436?

Medium severity, with a CVSS score of 4, published 6 August 2026.

Which products and versions are affected?

mermaid (npm) SEMVER:introduced=10.6.0,fixed=10.9.8.

Is there a fix for CVE-2026-71436?

Yes. mermaid (npm): upgrade to 10.9.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-71436 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-71436?

Check whether you run mermaid (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-71436: Mermaid infinite loop in XY Charts axis processing

CVE-2026-71436 · Severity: medium · CVSS 4 · Published 2026-08-06

Mermaid is a popular JavaScript library for generating diagrams from text. Its XY Chart feature is vulnerable to a denial-of-service attack when processing malformed axis configuration. An attacker can craft a specially-formatted diagram that causes the application to enter an infinite loop, consuming memory until the process crashes or becomes unresponsive, disrupting service availability for all users.

Technologies: mermaid (npm). Vendors: npm.

Quick answers

Is CVE-2026-71436 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-71436 being exploited in the wild.
How severe is CVE-2026-71436?: Medium severity, with a CVSS score of 4, published 6 August 2026.
Which products and versions are affected?: mermaid (npm) SEMVER:introduced=10.6.0,fixed=10.9.8.
Is there a fix for CVE-2026-71436?: Yes. mermaid (npm): upgrade to 10.9.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-71436 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-71436?: Check whether you run mermaid (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

mermaid (npm): upgrade to 10.9.8 or later
```
npm install mermaid@10.9.8
```

Technical details

The vulnerability exists in Mermaid's XY Chart rendering component, specifically in the setXAxisRangeData() function. When an X-axis is configured with invalid parameters (e.g., a zero-width range such as "1 --> 1"), the function enters an infinite loop that continuously appends elements to an array without a valid exit condition (CWE-835). Each iteration allocates memory, eventually causing a RangeError: Invalid array length or triggering garbage collection failures, leading to out-of-memory crashes. The vulnerability is triggered client-side when a user views a malicious diagram, requiring only passive user interaction (viewing a page). No authentication or elevated privileges are required. The attack vector is network-based; an attacker can embed the malicious diagram syntax in a web application or document. Patches have been released in Mermaid v11.16.1 (main branch) and v10.9.8 (v10 branch), implementing proper bounds checking and support for zero-width x-axis ranges.

Affected products

mermaid-js mermaid >=10.6.0, <=10.9.7; >=11.0.0-alpha.1, <=11.16.0

Identifiers

CVE-2026-71436
GHSA-2v8p-3f2j-5mp7

Timeline

2026-08-06: disclosed
2026-08-06: patched: Patched in v11.16.1 and v10.9.8

References

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