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CVE PROGRAM SOURCE RECORD5.3 Medium

CVE-2026-33173

Rails Active Storage has possible content type bypass via metadata in direct uploads

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

rails activestorage

  • >= 8.1.0.beta1, < 8.1.2.1affected
  • >= 8.0.0.beta1, < 8.0.4.1affected
  • < 7.2.3.1affected

References