Vulnerability in mermaid (CVE-2026-71436)
Summary
Vulnerability in mermaid (CVE-2026-71436). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 11.16.1 or later.
Original description
The description as published by the source.
Impact
Mermaid XY Charts are vulnerable to an infinite loop DoS attack in the setXAxisRangeData(), when configuring an X-Axis with invalid parameters.
As each loop appends an element to an array, this would generally only cause an RangeError: Invalid array length to appear after a few seconds, but may cause the page/JavaScript process to crash due to memory exhaustion, depending on the environment.
Proof-of-concept
xychart
x-axis 1 --> 1
line [1, 2]
Patches
This has been patched in https://github.com/mermaid-js/mermaid/commit/630aa7e5dd417e1f56bff2a1ce8df2c5ad08d289 and released in Mermaid v11.16.1.
A backport has been made for the v10 branch in ef60adc837d9d5107af21285f01e83dea309bd0a and was released in Mermaid v10.9.8
Workarounds
There are no known workarounds. Please update to the latest version or apply the patch.
References
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-71436 has been found in mermaid.
Risk of unauthorized operations or information disclosure.
What to do: upgrade mermaid to 11.16.1 or later.
If unsure, ask your IT team or search "mermaid CVE-2026-71436" on the vendor's site.
CVE-2026-71436 (mermaid) — CWE-835
Patched: 11.16.1 — apply immediately
Workaround: There are no known workarounds.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-835) exists in mermaid.
Check the vendor advisory for the affected versions of mermaid.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 11.16.1.
Workaround: There are no known workarounds.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'mermaid' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'mermaid' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
mermaidを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
There are no known workarounds.パッチが適用されるまでの応急処置として、There are no known workarounds. を実施。回避策の副作用 (機能低下) を確認した上で。
-
3Apply patch patch
Upgrade mermaid to 11.16.1ステージング環境で 11.16.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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4Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。