Vulnerability in Rails Activestorage
CVE-2026-33174
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 proxy delivery mode, the proxy 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. 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 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (48.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Rails Activestorage — versions >= 8.1.0.beta1, < 8.1.2.1, >= 8.0.0.beta1, < 8.0.4.1, < 7.2.3.1
- Rubyonrails Rails
Weakness classification (CWE)
References
- github.com/rails/rails/security/advisories/GHSA-r46p-8f7g-vvvg (Vendor Advisory)
- github.com/rails/rails/commit/2cd933c366b777f873d4d590127da2f4a25e4ba5 (Patch)
- github.com/rails/rails/commit/42012eaaa88dfc7d0030161b2bc8074a7bbce92a (Patch)
- github.com/rails/rails/commit/8159a9c3de3f27a2bcf2866b8bf9ceb9075e229b (Patch)
- github.com/rails/rails/releases/tag/v7.2.3.1 (Release Notes)
- github.com/rails/rails/releases/tag/v8.0.4.1 (Release Notes)
- github.com/rails/rails/releases/tag/v8.1.2.1 (Release Notes)
Frequently asked questions
- What is CVE-2026-33174?
- CVE-2026-33174 is a high-severity vulnerability in Rails Activestorage, classified under CWE-789. CVSS score: 7.5/10. Published 2026-03-24.
- How severe is CVE-2026-33174?
- High severity. CVSS v3 base score is 7.5 out of 10.