CVE-2026-113671
Received Received - Intake

ApostropheCMS AI Helper Server-Side Request Forgery

Publication date: 2026-10-20

Last updated on: 2026-10-20

Assigner: GitHub, Inc.

Description
ApostropheCMS is an open-source Node.js content management system. From 1.0.0-beta.10 until 1.0.0-beta.13 of the AI helper, an editor with image-generation capability can create a base64-generated image record without a stored provider URL and invoke image acceptance on a deployment using local relative storage with no trusted global base URL. The server resolves the fixed uploads path against a request-controlled Host-derived origin, enabling bounded server-side requests to an attacker-selected host, port, and HTTP origin, but not arbitrary-path retrieval or the stored-provider and absolute-storage configurations. This issue is fixed in AI helper 1.0.0-beta.13.

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Meta Information

Published
2026-10-20
Last Modified
2026-10-20
Generated
2026-10-20
AI Q&A
2026-10-20
EPSS Evaluated
N/A
NVD
CVE-2026-113671
EUVD
EUVD-2026-105220

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
apostrophecms apostrophe >= 4.25.0, < 4.33.0
@apostrophecms ai-helper >= 1.0.0-beta.10, < 1.0.0-beta.13

Helpful Resources

Exploitability

CWE
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KEV
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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.

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Executive Summary

This is a Server-Side Request Forgery (SSRF) vulnerability in ApostropheCMS's AI helper plugin versions 1.0.0-beta.10 through 1.0.0-beta.12. An authenticated editor with low privileges can manipulate the Host header in HTTP requests to force the server to make outbound GET requests to arbitrary origins. The server constructs image fetch URLs using the Host header-derived baseUrl when no global base URL is configured, and the accept route lacks proper authorization checks.

The attacker first generates a base64 AI image, then sends a crafted PATCH request with a malicious Host header, causing the server to fetch an internal or external resource at a fixed path.

Detection Guidance

Check if your ApostropheCMS instance uses @apostrophecms/ai-helper versions between 1.0.0-beta.10 and 1.0.0-beta.12. Inspect network logs for outbound requests to unexpected hosts or ports originating from the server. Look for PATCH requests with manipulated Host headers targeting the image acceptance endpoint.

Impact Analysis

An attacker with low-privilege access could exploit this to make the server send requests to internal systems or external hosts, potentially accessing sensitive data or services. This could lead to information disclosure, internal network reconnaissance, or further attacks against connected systems.

Compliance Impact

This vulnerability could impact compliance by potentially exposing sensitive data through unauthorized server-side requests. For GDPR, it may violate data protection principles if personal data is accessed. For HIPAA, it could risk unauthorized access to protected health information if internal systems are compromised.

Mitigation Strategies

Upgrade @apostrophecms/ai-helper to version 1.0.0-beta.13 or later. Configure a global base URL in your ApostropheCMS settings to prevent Host header manipulation. Use absolute storage URLs instead of relative paths. Implement egress controls to block unauthorized outbound requests from the server.

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