CVE-2026-73037

Received Received - Intake

Reflected XSS in Next AI Draw.io via MCP Query Parameter

Publication date: 2026-08-13

Last updated on: 2026-08-13

Assigner: VulnCheck

Description

Next AI Draw.io 0.2.1 through 0.4.16 contains a reflected cross-site scripting vulnerability in the mcp query parameter that is interpolated without escaping into HTML and JavaScript. Attackers can craft malicious URLs to execute arbitrary JavaScript in the localhost origin, enabling exfiltration of diagram sessions and API data.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-13

Last Modified

2026-08-13

Generated

2026-08-14

AI Q&A

2026-08-14

EPSS Evaluated

N/A

NVD

CVE-2026-73037

EUVD

EUVD-2026-58196

Affected Vendors & Products

Vendor	Product	Version / Range
next_ai	draw_io	From 0.2.1 (inc) to 0.4.16 (inc)
next-ai	draw.io	From 0.2.1 (inc) to 0.4.16 (inc)
next-ai	mcp-server	to 0.2.1 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Attack-Flow Graph

Executive Summary

CVE-2026-73037 is a reflected cross-site scripting (XSS) vulnerability in Next AI Draw.io versions 0.2.1 through 0.4.16. The flaw occurs because the application does not properly sanitize the 'mcp' query parameter before using it in HTML and JavaScript contexts. Attackers can craft malicious URLs that execute arbitrary JavaScript in the localhost origin when visited by a user.

Detection Guidance

To detect this vulnerability, check if your system is running Next AI Draw.io versions 0.2.1 through 0.4.16. Inspect network traffic for requests containing the unsanitized 'mcp' query parameter in URLs targeting localhost ports. Look for suspicious JavaScript execution in browser consoles when accessing these URLs.

Impact Analysis

This vulnerability allows attackers to execute arbitrary JavaScript in your browser when you visit a specially crafted URL. This could lead to theft of sensitive data like diagram sessions or API data stored by the application. Since it executes in the localhost origin, it may bypass some browser security restrictions.

Mitigation Strategies

Immediately update Next AI Draw.io to the latest patched version. If an update is unavailable, disable the embedded MCP HTTP server or block access to localhost ports used by the vulnerable component. Implement input validation to sanitize the 'mcp' query parameter before processing.

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