Rails Active Storage has a possible DoS vulnerability in proxy mode via multi-range requests
### Impact Active Storage's proxy controller does not limit the number of byte ranges in an HTTP Range header. A request with thousands of small ranges causes disproportionate CPU usage compared to a normal request for the same file, possibly resulting in a DoS vulnerability. ### Releases The fixed releases are available at the normal locations. ### Credit This issue was responsibly reported by Hackerone researcher [thwin_htet](https://hackerone.com/thwin_htet).
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-33658US | medium6.5 | — | ||
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
Active Storage's proxy controller does not limit… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/rails/railsPACKAGE
- 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-p9fm-f462-ggrgWEB
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activestorage/CVE-2026-33658.ymlWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-33658ADVISORY
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