CVE-2026-33173 (GCVE-0-2026-33173)

Vulnerability from cvelistv5 – Published: 2026-03-23 23:21 – Updated: 2026-03-24 15:12
VLAI
Title
Rails Active Storage has possible content type bypass via metadata in direct uploads
Summary
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.
Severity
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
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-925 - Improper Verification of Intent by Broadcast Receiver
Assigner
References
Impacted products
Vendor Product Version
rails activestorage Affected: >= 8.1.0.beta1, < 8.1.2.1
Affected: >= 8.0.0.beta1, < 8.0.4.1
Affected: < 7.2.3.1
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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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