CVE-2026-71436 mermaid-js CVE debrief

Who should care

Defenders responsible for systems using Mermaid versions 10.6.0 through 10.9.8 and 11.16.1 should assess exposure and apply patches or mitigations as needed. This includes reviewing system configurations, monitoring for potential attacks, and implementing compensating controls where necessary. Defenders should also prioritize verifying exposure in systems using affected versions and apply patches or mitigations as needed. This may involve coordinating with

Why it matters

CVE-2026-71436 is a denial-of-service vulnerability affecting Mermaid's XY Charts feature. Defenders should prioritize verifying exposure in systems using affected versions and apply patches or mitigations as needed.

• Potential denial-of-service attacks
• System crashes due to memory exhaustion
• RangeError exceptions in affected versions

Technical summary

The vulnerability is caused by an infinite loop in the setXAxisRangeData function when configuring an X-Axis with invalid parameters. This can lead to a RangeError or a crash due to memory exhaustion. The issue affects Mermaid versions 10.6.0 through 10.9.8 and 11.16.1, and is fixed in versions 10.9.8 and 11.16.1. Defenders should prioritize verifying exposure in systems using affected versions and apply patches or mitigations as needed. The vulnerability has a CVSS score of 5.3 and a severity of MEDIUM. The CVE record and NVD entry provide details on the vulnerability, including its description, affected versions, and fixed versions.

Defensive priority

Defenders should prioritize verifying exposure in systems using Mermaid versions 10.6.0 through 10.9.8 and 11.16.1, and apply patches or mitigations as needed.

Recommended defensive actions

• Verify Mermaid version and check for exposure
• Apply patches or mitigations for affected versions
• Monitor systems for potential denial-of-service attacks
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, affected versions, and fixed versions. However, there is limited information on potential exploits or attacks.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.