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.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-qcfx-2mfw-w4cg Rails Active Storage has possible content type bypass via metadata in direct uploads
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 24 Mar 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-1287
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L'}

threat_severity

Moderate


Tue, 24 Mar 2026 10:45:00 +0000

Type Values Removed Values Added
First Time appeared Rails
Rails activestorage
Vendors & Products Rails
Rails activestorage

Tue, 24 Mar 2026 02:30:00 +0000

Type Values Removed Values Added
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.
Title Rails Active Storage has possible content type bypass via metadata in direct uploads
Weaknesses CWE-925
References
Metrics cvssV4_0

{'score': 5.3, 'vector': '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'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-23T23:21:29.843Z

Reserved: 2026-03-17T22:16:36.719Z

Link: CVE-2026-33173

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-24T00:16:28.457

Modified: 2026-03-24T00:16:28.457

Link: CVE-2026-33173

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-03-23T23:21:29Z

Links: CVE-2026-33173 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-03-24T10:29:58Z

Weaknesses