CVE-2026-33173

Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, `DirectUploadsController` accepts arbitrary metadata from the client and persists it on the blob. Because internal flags like `identified` and `analyzed` are stored in the same metadata hash, a direct-upload client can set these flags to skip MIME detection and analysis. This allows an attacker to upload arbitrary content while claiming a safe `content_type`, bypassing any validations that rely on Active Storage's automatic content type identification. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

The following products are affected by CVE-2026-33173 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-33173.

URL	Resource
https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53
https://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3e
https://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0
https://github.com/rails/rails/releases/tag/v7.2.3.1
https://github.com/rails/rails/releases/tag/v8.0.4.1
https://github.com/rails/rails/releases/tag/v8.1.2.1
https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg
https://nvd.nist.gov/vuln/detail/CVE-2026-33173
https://www.cve.org/CVERecord?id=CVE-2026-33173