CVE-2026-53957
Received Received - Intake

Authorization Header Exposure in Contentful MCP Server

Publication date: 2026-09-15

Last updated on: 2026-09-15

Assigner: GitHub, Inc.

Description
Contentful MCP Server is a Model Context Protocol server for the Contentful Management API. Prior to @contentful/mcp-server 1.7.19 and @contentful/mcp-tools 0.4.5, export_space and import_space in packages/mcp-tools/src/tools/jobs/space-to-space-migration/exportSpace.ts and packages/mcp-tools/src/tools/jobs/space-to-space-migration/importSpace.ts expose host, proxy, rawProxy, and insecure network options to LLM-controlled tool arguments and combine those options with the server's CONTENTFUL_MANAGEMENT_TOKEN. After space_to_space_migration_handler enables the migration tools, a direct MCP call or prompt injection through attacker-controlled Contentful content can redirect Contentful Management API requests and their Authorization header to an attacker-controlled host or proxy. The regular tools that use createToolClient are unaffected because those tools pin the host from server configuration. Exposure of the personal access token permits persistent out-of-band access to every Contentful space within the token's scope. This issue is fixed in @contentful/mcp-server 1.7.19 and @contentful/mcp-tools 0.4.5.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-09-15
Last Modified
2026-09-15
Generated
2026-09-15
AI Q&A
2026-09-15
EPSS Evaluated
N/A
NVD
CVE-2026-53957
EUVD
EUVD-2026-78590

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
contentful mcp-server 1.7.19
contentful mcp-tools 0.4.5
contentful mcp-tools From 0.4.1 (exc)
contentful mcp-server From 1.7.15 (exc)

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-918 The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

CVE-2026-53957 is a Server-Side Request Forgery (SSRF) vulnerability in the Contentful MCP Server. It affects the export_space and import_space tools which previously accepted LLM-controlled parameters like host, proxy, and headers. These parameters could redirect Content Management API (CMA) requests—including the server's Personal Access Token (PAT)—to attacker-controlled endpoints via prompt injection or direct tool calls. The vulnerability allowed attackers to capture the PAT by forcing requests to malicious servers or proxies.

Detection Guidance

To detect this vulnerability, check if your Contentful MCP server is running a vulnerable version (<=1.7.15 for mcp-server or <=0.4.1 for mcp-tools). Inspect network traffic for unexpected outbound connections to unknown hosts or proxies. Review logs for unusual API requests or PAT exposure. Commands like 'curl -s https://your-server/status | grep version' or 'ss -tulnp | grep <unexpected-ports>' may help identify suspicious activity.

Impact Analysis

If exploited, this vulnerability could allow an attacker to capture your Contentful Management API Personal Access Token (PAT). This would grant persistent access to all Contentful spaces within the token's scope, enabling unauthorized data exfiltration, modification, or deletion. Attackers could also redirect API requests to malicious endpoints, potentially intercepting sensitive data in transit.

Compliance Impact

This vulnerability could lead to unauthorized access and data breaches, violating GDPR's data protection requirements and HIPAA's safeguards for protected health information. A successful exploit may result in unauthorized data exposure, triggering mandatory breach notifications and potential regulatory fines under these standards.

Mitigation Strategies

Upgrade to @contentful/mcp-server 1.7.19 or later and @contentful/mcp-tools 0.4.5 or later to patch the vulnerability. Remove any existing LLM tool calls or configurations that use export_space or import_space with host, proxy, rawProxy, headers, or config parameters. Review server logs for unusual API requests or PAT exposure.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-53957. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart