Cross-Site Scripting (XSS) in mermaid (CVE-2025-54880)
Summary
Cross-site scripting in mermaid (CVE-2025-54880). Risk of unauthorized operations or information disclosure. Exploitable via iconText. Mitigation: upgrade to 11.10.0 or later.
Original description
The description as published by the source.
Summary
In the default configuration of mermaid 11.9.0, user supplied input for architecture diagram icons is passed to the d3 html() method, creating a sink for cross site scripting.
Details
Architecture diagram service iconText values are passed to the d3 html() method, allowing malicious users to inject arbitrary HTML and cause XSS when mermaid-js is used in it's default configuration.
The vulnerability lies here:
export const drawServices = async function (
db: ArchitectureDB,
elem: D3Element,
services: ArchitectureService[]
): Promise {
for (const service of services) {
/** ... **/
} else if (service.iconText) {
bkgElem.html(
`${await getIconSVG('blank', { height: iconSize, width: iconSize, fallbackPrefix: architectureIcons.prefix })}`
);
const textElemContainer = bkgElem.append('g');
const fo = textElemContainer
.append('foreignObject')
.attr('width', iconSize)
.attr('height', iconSize);
const divElem = fo
.append('div')
.attr('class', 'node-icon-text')
.attr('style', `height: ${iconSize}px;`)
.append('div')
.html(service.iconText); // <- iconText passed into innerHTML
/** ... **/
};
};
This issue was introduced with 734bde38777c9190a5a72e96421c83424442d4e4, around 15 months ago, which was released in v11.1.0.
PoC
Render the following diagram a…
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
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-2025-54880 has been found in mermaid.
Attackers can target a specific entry point like iconText over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade mermaid to 11.10.0 or later.
If unsure, ask your IT team or search "mermaid CVE-2025-54880" on the vendor's site.
CVE-2025-54880 (mermaid) — CWE-79
Attack surface: iconText
Patched: 11.10.0 — apply immediately
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.
Cross-site scripting (XSS) (CWE-79) exists in mermaid. Attackers reach the vulnerable code path via iconText.
Check the vendor advisory for the affected versions of mermaid. Attack surface: iconText.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 11.10.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
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 patch patch
Upgrade mermaid to 11.10.0ステージング環境で 11.10.0 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。
-
3Post-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。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com