Rails Active Storage has a possible DoS vulnerability when in 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. ### Credit This issue was responsibly reported by Hackerone user [pirikara](https://hackerone.com/pirikara)
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-33174US | high7.5 | — | ||
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, when serving files through Active Storage's prox… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/rails/railsPACKAGE
- https://github.com/rails/rails/commit/2cd933c366b777f873d4d590127da2f4a25e4ba5WEB
- https://github.com/rails/rails/commit/42012eaaa88dfc7d0030161b2bc8074a7bbce92aWEB
- https://github.com/rails/rails/commit/8159a9c3de3f27a2bcf2866b8bf9ceb9075e229bWEB
- https://github.com/rails/rails/releases/tag/v7.2.3.1WEB
- https://github.com/rails/rails/releases/tag/v8.0.4.1WEB
- https://github.com/rails/rails/releases/tag/v8.1.2.1WEB
- https://github.com/rails/rails/security/advisories/GHSA-r46p-8f7g-vvvgWEB
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