GitHub Advisoryadvisory · RubyGems
GHSA-qcfx-2mfw-w4cg Rails Active Storage has possible content type bypass via metadata in direct uploads
MEDIUM
Official page ↗
- Aliases
- CVE-2026-33173
- Ecosystem
- RubyGems
- Packages
- activestorage
- Severity
- Moderate
- CVSS 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
- Weaknesses
- CWE-925
- Reviewed
- 2026-03-23
Affected packages
• RubyGems activestorage: >= 8.1.0.beta1, < 8.1.2.1 → fixed in 8.1.2.1
• RubyGems activestorage: >= 8.0.0.beta1, < 8.0.4.1 → fixed in 8.0.4.1
• RubyGems activestorage: < 7.2.3.1 → fixed in 7.2.3.1
Description
Impact
Active Storage's `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 malicious direct-upload client could set these flags.
Releases
The fixed releases are available at the normal locations.
Credit
This was responsible reported by Hackerone researcher pwnie
Related
Alias · CVE (1)
- CVE-2026-33173 Active Storage allows users to attach cloud and local files in Rails applications. vulnerability
Weakness · CWE (1)
- CWE-925 Improper Verification of Intent by Broadcast Receiver weakness
References
- https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg web
- https://nvd.nist.gov/vuln/detail/CVE-2026-33173 advisory
- https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53 web
- https://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3e web
- https://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0 web
- https://github.com/rails/rails package
- https://github.com/rails/rails/releases/tag/v7.2.3.1 web
- https://github.com/rails/rails/releases/tag/v8.0.4.1 web
- https://github.com/rails/rails/releases/tag/v8.1.2.1 web
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activestorage/CVE-2026-33173.yml web