ACTIVESTORAGE · GHSA-hfr4-8rjc-97m2 · Package
FIX → 8.1.4.1 +1
Active Storage's Google Cloud Storage direct-upload URLs do not bind the declared file size, so a client can upload a larger file than it declared. The stored blob keeps the declared size, which can bypass application size validations and quotas.
first public Nov 4, 2026 · 1 source
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Applications that use Active Storage with Google Cloud Storage and accept direct browser or client uploads are exposed. Apps on S3, Azure or local disk services, or apps that do not use direct uploads, are not affected by this flaw.
Not affected if no-direct-uploads, no-gcs-service, static-export
Who cares activestorage, google-cloud-storage, rails, ruby
activestorage in Gemfile.lock and compare its version with the fixed ranges.ActiveStorage with the google service in config/storage.yml and accepts direct uploads.x-goog-content-length-range in .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.
The fixed releases sign an x-goog-content-length-range header that matches the blob's declared byte_size and return it from headers_for_direct_upload, so Cloud Storage rejects an upload body of any other size. Browsers send this header with the direct upload, so a bucket's CORS configuration must list x-goog-content-length-range in responseHeader, or browser direct uploads fail after the upgrade. The Active Storage CHANGELOG and the CORS example in the Active Storage guide show the change.
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responseHeaderUpgrade to 8.1.4.1 +1
activestorage 8.1.4.1 for the 8.1 lineactivestorage 8.0.5.2 for the 8.0 linex-goog-content-length-range to the bucket CORS responseHeader list, or browser direct uploads fail.The fixed releases are available at the normal locations.
Patches for those who cannot upgrade at once:
This issue was responsibly reported by HackerOne researcher f4cts.