CVE-2026-33173

Description

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.

References

• 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