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.

The following products are affected by CVE-2026-33174 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-33174.

URL	Resource
https://github.com/rails/rails/commit/2cd933c366b777f873d4d590127da2f4a25e4ba5
https://github.com/rails/rails/commit/42012eaaa88dfc7d0030161b2bc8074a7bbce92a
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/v8.0.4.1
https://github.com/rails/rails/releases/tag/v8.1.2.1
https://github.com/rails/rails/security/advisories/GHSA-r46p-8f7g-vvvg
https://nvd.nist.gov/vuln/detail/CVE-2026-33174
https://www.cve.org/CVERecord?id=CVE-2026-33174