Strapi Upload Plugin MIME Validation Bypass via Content API
Date: 2026-05
Affected: npm/@strapi/upload
Attack vector: other
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2026-22707
CWE: CWE-434
CWE-693

### Summary of CVE-2026-22707 Vulnerability Details - CVE: CVE-2026-22707 - CVSS v3.1 Vector: `CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N` (5.3 — Medium) - Affected Versions: `@strapi/upload` <=5.33.2 - How to Patch: Immediately update your Strapi to >=5.33.3 ### Description of CVE-2026-22707 In Strapi versions prior to 5.33.3, the Upload plugin's Content API endpoints did not enforce the administrator-configured MIME type restrictions (`plugin.upload.security.allowedTypes` and `deniedTypes`). The same restrictions were correctly enforced on the Admin Panel upload path. The upload plugin's `enforceUploadSecurity` security check was invoked in the admin upload controller but was missing from the Content API controller. The Content API handlers `uploadFiles` and `replaceFile` (and the `upload` wrapper that dispatches to them) called the underlying upload service directly, bypassing both the magic-byte MIME detection and the configured allow/deny lists. An authenticated user with the Content API upload permission could therefore upload file types the administrator had explicitly disallowed, including HTML and SVG content. In deployments serving uploaded files from the same origin as the admin panel (default), an attacker could upload an HTML or SVG file that, when opened directly by an admin, executed JavaScript in the admin origin, enabling admin-session hijack and authenticated administrative actions against the admin API. The patch introduces a shar


Mitigations:

Architectural layers (MAESTRO):