# CVE-2025-54880: Mermaid improper sanitization of architecture diagram iconText leading to XSS

Source: https://junglewise.ai/threats/cve-2025-54880-mermaid-improper-sanitization-of-architecture-diagram-icontext  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-08-19. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2025-54880 · Severity: medium · CVSS 4 · Published 2025-08-19

Mermaid is a JavaScript library used to render diagrams from text descriptions on websites. The architecture diagram feature fails to sanitize user-supplied text for icon labels, allowing attackers to inject malicious HTML and JavaScript code. When a website displays user-created or user-controlled diagrams without additional protections, an attacker can execute arbitrary JavaScript in visitors' browsers, potentially stealing session data, credentials, or performing actions on behalf of the victim.

Technologies: [mermaid (npm)](https://junglewise.ai/threats/technologies/mermaid). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2025-54880 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-54880 being exploited in the wild.

**How severe is CVE-2025-54880?** Medium severity, with a CVSS score of 4, published 19 August 2025.

**Which products and versions are affected?** mermaid (npm) SEMVER:introduced=11.1.0,fixed=11.10.0.

**Is there a fix for CVE-2025-54880?** Yes. mermaid (npm): upgrade to 11.10.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2025-54880 attacked?** It is attacked over the network.

**Am I affected by CVE-2025-54880?** 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 11.10.0 or later

  ```sh
  npm install mermaid@11.10.0
  ```


## Technical details

The vulnerability is a cross-site scripting (XSS) flaw introduced in Mermaid v11.1.0 and present through v11.9.0. The architecture diagram rendering code passes the `iconText` parameter directly to the d3 `html()` method via `.html(service.iconText)`, which treats the input as raw HTML rather than escaped text. No validation or sanitization occurs on this user-controlled input before insertion into the DOM. The attack is network-reachable and requires no authentication, but does require user interaction to render a malicious diagram. An attacker can craft a diagram containing JavaScript payloads in the iconText field that execute in the browser context. The vulnerability was patched in version 11.10.0.

## Affected products

- Mermaid Mermaid 11.1.0 through 11.9.0

## Identifiers

- CVE-2025-54880
- GHSA-8gwm-58g9-j8pw

## Timeline

- 2025-08-19: disclosed
- 2025-08-19: patched: Fixed in version 11.10.0

## References

- [https://github.com/mermaid-js/mermaid/security/advisories/GHSA-8gwm-58g9-j8pw](https://github.com/mermaid-js/mermaid/security/advisories/GHSA-8gwm-58g9-j8pw)

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