# CVE-2026-33174: Rails Active Storage has a possible DoS vulnerability when in proxy mode via Range requests

Source: https://junglewise.ai/threats/cve-2026-33174-rails-active-storage-has-a-possible-dos-vulnerability-when-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-03-23. Updated: 2026-05-11  
License: CC BY 4.0 with a link back

CVE-2026-33174 · Severity: medium · CVSS 4 · Published 2026-03-23

### 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)

Technologies: [activestorage (RubyGems)](https://junglewise.ai/threats/technologies/activestorage). Vendors: [RubyGems](https://junglewise.ai/threats/vendors/rubygems).

## Quick answers

**Is CVE-2026-33174 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-33174 being exploited in the wild.

**How severe is CVE-2026-33174?** Medium severity, with a CVSS score of 4, published 23 March 2026.

**Which products and versions are affected?** activestorage (RubyGems) ECOSYSTEM:introduced=8.1.0.beta1,fixed=8.1.2.1.

**Is there a fix for CVE-2026-33174?** Yes. activestorage (RubyGems): upgrade to 8.1.2.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-33174?** Check whether you run activestorage (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- activestorage (RubyGems): upgrade to 8.1.2.1 or later

  ```sh
  bundle update activestorage
  ```


## Affected products

- activestorage (RubyGems) ECOSYSTEM:introduced=8.1.0.beta1,fixed=8.1.2.1

## Identifiers

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

## References

- [https://github.com/rails/rails/security/advisories/GHSA-r46p-8f7g-vvvg](https://github.com/rails/rails/security/advisories/GHSA-r46p-8f7g-vvvg)
- [https://github.com/rails/rails/commit/2cd933c366b777f873d4d590127da2f4a25e4ba5](https://github.com/rails/rails/commit/2cd933c366b777f873d4d590127da2f4a25e4ba5)
- [https://github.com/rails/rails/commit/42012eaaa88dfc7d0030161b2bc8074a7bbce92a](https://github.com/rails/rails/commit/42012eaaa88dfc7d0030161b2bc8074a7bbce92a)
- [https://github.com/rails/rails/commit/8159a9c3de3f27a2bcf2866b8bf9ceb9075e229b](https://github.com/rails/rails/commit/8159a9c3de3f27a2bcf2866b8bf9ceb9075e229b)
- [https://github.com/rails/rails/releases/tag/v7.2.3.1](https://github.com/rails/rails/releases/tag/v7.2.3.1)
- [https://github.com/rails/rails/releases/tag/v8.0.4.1](https://github.com/rails/rails/releases/tag/v8.0.4.1)

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