CVE-2026-331735.3MediumCWE-925

CVE-2026-33173: Rails Active Storage has possible content type bypass via metadata in direct uploads

rails · activestorage

Affected: rails activestorage · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.4%probability of exploitation in the next 30 days

35th percentile

050100

Higher than 35% of scored CVEs

5.3MediumCVSS 4.0

LowMediumHighCrit.

DescriptionCVE.org

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 products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

rails · activestorage>= 8.1.0.beta1, < 8.1.2.1; >= 8.0.0.beta1, < 8.0.4.1; < 7.2.3.1

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Improper Verification of Intent by Broadcast Receiver · Access Control
Vendor: rails
Published: March 2026
Band: Unlikely (under 1%), March 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-33173 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.