CVE-2026-53711
Received Received - Intake

Stored XSS in MCP Context Forge Admin UI

Publication date: 2026-10-13

Last updated on: 2026-10-13

Assigner: GitHub, Inc.

Description
MCP Context Forge provides an MCP Admin UI for managing gateway resources. From 0.2.0 until 0.3.1, the Global Prompts feature stores a prompt template without sufficient output encoding before the MCP Admin UI renders it. An authenticated attacker can save markup containing script-capable event handlers, and the code executes when another user views the saved prompt. The stored cross-site scripting can alter the interface, present phishing content, observe keystrokes available to the page, and act with the viewer's browser session. This issue is fixed in version 0.3.1.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-13
Last Modified
2026-10-13
Generated
2026-10-13
AI Q&A
2026-10-13
EPSS Evaluated
N/A
NVD
CVE-2026-53711
EUVD
EUVD-2026-98770

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
IBM mcp-context-forge >= 0.2.0, < 0.3.1

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
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

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability is a stored cross-site scripting (XSS) issue in MCP Context Forge versions 0.2.0 to 0.3.1. The Global Prompts feature saves prompt templates without proper output encoding. An attacker can inject malicious scripts via event handlers in the prompt template. When another user views the saved prompt, the script executes in their browser session.

Detection Guidance

Check MCP Context Forge versions between 0.2.0 and 0.3.1. Inspect saved prompt templates for script-capable event handlers or unusual markup. Review browser console logs for unexpected script execution when viewing prompts.

Impact Analysis

An attacker could alter the MCP Admin UI interface, present fake login or phishing content, capture keystrokes, or perform actions on behalf of the user. Since the script runs in the user's browser session, it may access sensitive data or session tokens.

Compliance Impact

This vulnerability could lead to unauthorized access to personal data, violating GDPR and HIPAA requirements for data protection and confidentiality. It may result in data breaches, unauthorized disclosure, or loss of control over sensitive information.

Mitigation Strategies

Upgrade MCP Context Forge to version 0.3.1 or later. Remove or sanitize any suspicious prompt templates. Implement input validation for prompt content. Monitor for unauthorized changes to UI or phishing attempts.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-53711. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart