What’s Vulnerable › Vulnerabilities

CVE-2026-53711: MCP ContextForge: Global Prompts stored cross-site scripting compromises the Admin UI

• Severity: medium (CVSS 5.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-13 · updated 2026-10-16
• Weakness: CWE-79

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.

Affected products

• IBM mcp-context-forge: from 0.2.0, < 0.3.1

References

• https://github.com/IBM/mcp-context-forge/commit/acd16196158f9a393187551b21a2fc61650f2e3d
• https://github.com/IBM/mcp-context-forge/pull/337
• https://github.com/IBM/mcp-context-forge/releases/tag/v0.3.1
• https://github.com/IBM/mcp-context-forge/security/advisories/GHSA-x6gc-rm5j-55mw
• https://github.com/IBM/mcp-context-forge/security/advisories/GHSA-x6gc-rm5j-55mw

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