CVE-2026-33174CWE-789

Rails Active Storage has a possible DoS vulnerability when in proxy mode via Range requests

Medium · published March 23, 2026

CVSS v4.0
6.6
EPSS
1%
Percentile
49.1
In the wild
Unconfirmed
What it is

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 record
Technical detail
CVSS v4.0
6.6 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U
EPSS
0.00621 · 49.1th percentile
Weakness
CWE-789 · Memory Allocation with Excessive Size Value
Published
2026-03-23T23:24Z
EPSS history
Timeline
  • 23 MAR 23:24Z
    Rails Active Storage has a possible DoS vulnerability when in proxy mode via Range requests
    cvelistv5