CVE-2026-1260855.3MediumCWE-602

CVE-2026-126085: Active Storage: Possible circumvention of file size limits in Active Storage direct uploads to Google Cloud Storage

rails

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

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

0.5%probability of exploitation in the next 30 days

42nd percentile

050100

Higher than 42% of scored CVEs

5.3MediumCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

Active Storage makes it simple to upload and reference files in cloud services and attach those files to Active Record objects. Prior to 8.1.4.1 and 8.0.5.2, ActiveStorage::Service::GCSService#url_for_direct_upload does not bind the declared content length into the signed direct-upload URL, and #headers_for_direct_upload returns no length constraint, so the URL authorizes an upload body of any size. A direct-upload client could store a file larger than the byte_size it declared, and the resulting blob keeps the declared size, possibly bypassing application file size validations and quotas. This is the weakness that CVE-2020-8162 fixed in the S3 service. Applications that store files in Google Cloud Storage and accept direct uploads are affected. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.

Affected products1

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

rails · rails>= 8.1, < 8.1.4.1; < 8.0.5.2

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: Client-Side Enforcement of Server-Side Security · Input Validation and Logic
Vendor: rails
Published: November 2026
Band: Unlikely (under 1%), November 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-126085 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.