[CVE-2026-33174] Possible DoS vulnerability in Active Storage proxy mode via Range requests

Impact

When serving files through Active Storage’s Blobs::ProxyController, the controller loads the entire requested byte range into memory before sending it. A request with a large or unbounded Range header (e.g. bytes=0-) could cause the server to allocate memory proportional to the file size, possibly resulting in a DoS vulnerability through memory exhaustion.

Releases

The fixed releases are available at the normal locations.

  • CVE-2026-33174
  • GHSA-r46p-8f7g-vvvg

Versions affected

  • activestorage >= 8.1, < 8.1.2.1 (patched in 8.1.2.1)
  • activestorage >= 8.0, < 8.0.4.1 (patched in 8.0.4.1)
  • activestorage < 7.2.3.1 (patched in 7.2.3.1)

Patches

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