CVE-2026-33173

MEDIUM

Active Storage <8.1.2.1 - Auth Bypass

Title source: llm
STIX 2.1

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 v3 5.3
EPSS 0.0001
EPSS Percentile 3.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-925
Status published
Products (5)
rails/activestorage < 7.2.3.1
rails/activestorage >= 8.0.0.beta1, < 8.0.4.1
rails/activestorage >= 8.1.0.beta1, < 8.1.2.1
rubygems/activestorage 8.1.0.beta1 - 8.1.2.1RubyGems
rubyonrails/rails < 7.2.3.1
Published Mar 24, 2026
Tracked Since Mar 24, 2026