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

- 種別: advisory
- 重大度: medium
- 関連技術: nodejs
- CVE: CVE-2026-113671
- 公開日時: 2026-10-20T18:11:01.000Z
- 情報源: GitHub Advisory Database (https://github.com/advisories/GHSA-527g-ff96-x6wj)
- パーマリンク: https://vulnpulse.app/items/ghsa-ghsa-527g-ff96-x6wj

影響: npm:@apostrophecms/ai-helper >= 1.0.0-beta.10, < 1.0.0-beta.13 → 1.0.0-beta.13
Summary The @apostrophecms/ai-helper package builds the URL for a server-side image fetch by resolving a storage-relative path against req.baseUrl. When the site does not set a global base URL (the default), req.baseUrl is derived from the incoming HTTP Host header. An authenticated editor can generate a base64 AI image (which is persisted without a stored url) and then send an unauthorized PATCH accept request with an attacker-chosen Host header. The server then issues an outbound GET to the a…