Path Traversal in Rails Activestorage
CVE-2026-33195
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 `DiskService#path_for` does not validate that the resolved filesystem path remains within the storage root directory. If a blob key containing path traversal sequences (e.g. `../`) is used, it could allow reading, writing, or deleting arbitrary files on the server. Blob keys are expected to be trusted strings, but some applications could be passing user input as keys and would be affected. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (45.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 45.9% 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
- https://github.com/rails/rails/security/advisories/GHSA-9xrj-h377-fr87 (Vendor Advisory)
- https://github.com/rails/rails/commit/4933c1e3b8c1bb04925d60347be9f69270392f2c (Patch)
- https://github.com/rails/rails/commit/9b06fbc0f504b8afe333f33d19548f3b85fbe655 (Patch)
- https://github.com/rails/rails/commit/a290c8a1ec189d793aa6d7f2570b6a763f675348 (Patch)
- https://github.com/rails/rails/releases/tag/v7.2.3.1 (Release Notes)
- https://github.com/rails/rails/releases/tag/v8.0.4.1 (Release Notes)
- https://github.com/rails/rails/releases/tag/v8.1.2.1 (Release Notes)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-33195?
- CVE-2026-33195 is a critical-severity vulnerability in Rails Activestorage, classified under Path Traversal. CVSS score: 9.8/10. Published 2026-03-24.
- How severe is CVE-2026-33195?
- Critical severity. CVSS v3 base score is 9.8 out of 10.