CVE-2026-33173
Rails Active Storage has possible content type bypass via metadata in direct uploads
- State
- Published
- Severity
- 5.3 Medium
- Published
- Mar 23, 2026
- Updated
- Mar 24, 2026
- Reserved
- Mar 17, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.3 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N | GitHub_M |
Weaknesses
- CWE-925 Improper Verification of Intent by Broadcast Receiver
Affected Products
| Product | Versions |
|---|---|
activestoragerails |
|
References
- https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg
- 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
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