Vulnerability in Rails

CVE-2026-126085

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.

Published .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

  • Rails — versions < 8.0.5.2, >= 8.1, < 8.1.4.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-126085?
CVE-2026-126085 is a medium-severity vulnerability in Rails, classified under CWE-602. CVSS score: 5.3/10. Published 2026-11-10.
How severe is CVE-2026-126085?
Medium severity. CVSS v3 base score is 5.3 out of 10.