# CVE-2026-33173

## Summary

- **CVE ID:** CVE-2026-33173
- **Severity:** MEDIUM
- **CVSS Score:** 5.3 (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)
- **CWE:** CWE-925
- **Published:** Mar 23, 2026
- **Last Modified:** Mar 24, 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.

## Affected Products

- rails — activestorage (>= 8.1.0.beta1, < 8.1.2.1)
- rails — activestorage (>= 8.0.0.beta1, < 8.0.4.1)
- rails — activestorage (< 7.2.3.1)

## References

- [CNA](https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg)
- [CNA](https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53)
- [CNA](https://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3e)
- [CNA](https://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0)
- [CNA](https://github.com/rails/rails/releases/tag/v7.2.3.1)
- [CNA](https://github.com/rails/rails/releases/tag/v8.0.4.1)
- [CNA](https://github.com/rails/rails/releases/tag/v8.1.2.1)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.39%
- **EPSS Percentile:** 32.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._