Resource exhaustion in Rails Activestorage
CVE-2026-33658
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 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. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (44.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 44.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.001
Affected products
- Rails Activestorage — versions >= 8.1.0, < 8.1.2.1, >= 8.0.0, < 8.0.4.1, < 7.2.3.1
- Rubyonrails Rails
Weakness classification (CWE)
References
- github.com/rails/rails/security/advisories/GHSA-p9fm-f462-ggrg (Vendor Advisory)
- github.com/rails/rails/releases/tag/v7.2.3.1 (Product, Release Notes)
- github.com/rails/rails/releases/tag/v8.0.4.1 (Product, Release Notes)
- github.com/rails/rails/releases/tag/v8.1.2.1 (Product, Release Notes)
- github.com/rubysec/ruby-advisory-db/blob/master/gems/activestorage/CVE-2026-336… (Third Party Advisory)
Frequently asked questions
- What is CVE-2026-33658?
- CVE-2026-33658 is a medium-severity vulnerability in Rails Activestorage, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 6.5/10. Published 2026-03-26.
- How severe is CVE-2026-33658?
- Medium severity. CVSS v3 base score is 6.5 out of 10.