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Vulnerability · Published Oct 20, 2026 · Assigned by GitHub_M

CVE-2026-113671ApostropheCMS: Host header controls server-side image fetch origin in @apostrophecms/ai-helper, enabling authenticated SSRF

Medium 4.3

In plain English

A medium-severity server-side request forgery in ai-helper from @apostrophecms. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.3%top 73.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
npm@apostrophecms/ai-helper1.0.0-beta.13GHSA-527g-ff96-x6wj

Affected products (as reported)

VendorProductVersions
apostrophecms apostrophe >= 4.25.0, < 4.33.0
@apostrophecms ai-helper >= 1.0.0-beta.10, < 1.0.0-beta.13

Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

References