Is there a public PoC exploit available for CVE-2026-71439?

Yes, a public proof-of-concept exploit is available for CVE-2026-71439. Prioritise patching immediately. EPSS: 0.4%.

Is there a patch available for CVE-2026-71439?

Yes, a patch is available for CVE-2026-71439. Update the affected software to the latest version immediately.

Mermaid CVE-2026-71439

Q: What is the CVSS score of CVE-2026-71439?

CVE-2026-71439 has a CVSS 4.0 base score of 5.3 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.4%.

EUVD-2026-54249 MEDIUM

Unchecked Input for Loop Condition (CWE-606)

2026-08-06 https://github.com/mermaid-js/mermaid

GHSA-rhh3-jpg6-66xh

Information Disclosure Red Hat Suse

5.3

CVSS 4.0 · Vendor: https://github.com/mermaid-js/mermaid

Severity by source

Vendor (https://github.com/mermaid-js/mermaid) PRIMARY

5.3 MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vuln.today AI

6.5 MEDIUM

Network-delivered diagram input, no privileges needed, but a user or server must trigger rendering; pure availability impact with no confidentiality or integrity effect.

3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

4.0 AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SUSE

MEDIUM

qualitative

Red Hat

6.5 MEDIUM

qualitative

Primary rating from Vendor (https://github.com/mermaid-js/mermaid).

CVSS VectorVendor: https://github.com/mermaid-js/mermaid

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Scope

Lifecycle Timeline

CVSS changed

Aug 06, 2026 - 22:22 NVD

5.3 (MEDIUM)

Source Code Evidence Fetched

Aug 06, 2026 - 20:37 vuln.today

Analysis Generated

Aug 06, 2026 - 20:37 vuln.today

CVE Published

Aug 06, 2026 - 20:01 cve.org

MEDIUM

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

9 npm packages depend on mermaid (9 direct, 1 indirect)

Ecosystem-wide dependent count for version 11.6.0.

DescriptionCVE.org

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

txt

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?_

https://github.com/mermaid-js/mermaid/commit/59b22fad2b3bb04f87a476c84a8a2b24679e607e
https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.16.1

AnalysisAI

Denial-of-service in Mermaid's radar-beta diagram renderer allows an attacker who can supply diagram input to trigger unbounded CPU and memory consumption by setting the ticks parameter to an arbitrarily large integer. Affected npm package versions >= 11.6.0 and < 11.16.1 perform no upper-bound validation on the ticks value, causing the JavaScript process - whether a browser tab or a server-side renderer - to freeze indefinitely until the OS terminates it due to OOM. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access

Submit crafted radar-beta Mermaid input

Delivery

Diagram reaches server-side renderer

Exploit

Unbounded tick loop consumes CPU/memory

Execution

JS process freezes or is OOM-killed

Impact

Service unavailability

Access

Submit crafted radar-beta Mermaid input

Delivery

Diagram reaches server-side renderer

Exploit

Unbounded tick loop consumes CPU/memory

Execution

JS process freezes or is OOM-killed

Impact

Service unavailability

Vulnerability AssessmentAI

Exploitation	Exploitation requires that the target application renders user-supplied Mermaid diagram content containing a radar-beta block with an attacker-controlled `ticks` value. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment	No vendor-supplied CVSS vector is available; independent assessment places this at medium severity (see assessed_cvss_vector). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	An attacker submits a crafted Mermaid radar-beta diagram containing `ticks 1000000000` (as shown in the public POC) to a documentation platform or wiki that renders user-supplied diagrams server-side. The Mermaid renderer enters an effectively infinite loop consuming 100% CPU and exhausting heap memory, causing the Node.js server process to become unresponsive or be killed by the OS OOM killer. …
Remediation	Upgrade the mermaid npm package to version 11.16.1 or later, which caps the `ticks` value at 32 via commit 59b22fad2b3bb04f87a476c84a8a2b24679e607e. … Detailed patch versions, workarounds, and compensating controls in full report.