ApostropheCMS is an open-source content management framework. Prior to version 3.5.3 of `@apostrophecms/import-export`, The `extract()` function in `gzip.js` constructs file-write paths using `fs.createWriteStream(path.join(exportPath, header.name))`. `path.join()` does not resolve or sanitise traversal segments such as `../`. It concatenates them as-is, meaning a tar entry named `../../evil.js` resolves to a path outside the intended extraction directory. No canonical-path check is performed before the write stream is opened. This is a textbook Zip Slip vulnerability. Any user who has been granted the Global Content Modify permission — a role routinely assigned to content editors and site managers — can upload a crafted `.tar.gz` file through the standard CMS import UI and write attacker-controlled content to any path the Node.js process can reach on the host filesystem. Version 3.5.3 of `@apostrophecms/import-export` fixes the issue.

Affected: npm: @apostrophecms/import-export

**Reported:** 2026-03-08 **Status:** patched and released in version 3.5.3 of `@apostrophecms/import-export`

---

## Product

| Field | Value | |---|---| | Repository | `apostrophecms/apostrophe` (monorepo) | | Affected Package | `@apostrophecms/import-export` | | Affected File | `packages/import-export/lib/formats/gzip.js` | | Affected Function | `extract(filepath, exportPath)` — lines ~132–157 | | Minimum Required Permission | **Global Content Modify** (any editor-level user with import access) |

---

## Vulnerability Summary

The `extract()` function in `gzip.js` constructs file-write paths using:

```js fs.createWriteStream(path.join(exportPath, header.name)) ```

`path.join()` does **not** resolve or sanitise traversal segments such as `../`. It concatenates them as-is, meaning a tar entry named `../../evil.js` resolves to a path **outside** the intended extraction directory. No canonical-path check is performed before the write stream is opened.

This is a textbook **Zip Slip** vulnerability. Any user who has been granted the **Global Content Modify** permission — a role routinely assigned to content editors and site managers — can upload a crafted `.tar.gz` file through the standard CMS import UI and write attacker-controlled content to **any path the Node.js process can reach on the host filesystem**.

---

## Security Impact

This vulnerability provides **unauthenticated-equivalent arbitrary file write** to any user with content editor permissions. The full impa…