Vulnerability Intelligence Report
Rails Active Storage has a possible DoS vulnerability when in proxy mode via Range requests
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.
No Active Exploit Signals
CVSS Base Score
6.6
MEDIUM
EPSS Probability:0.61%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
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Authentication
—
Weaponization
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SSVC Action
—
Weaknesses (CWE)
CWE-789 ↗CWE-789: Memory Allocation with Excessive Size Value
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| rails | activestorage | >= 8.1.0.beta1, < 8.1.2.1 (affected), >= 8.0.0.beta1, < 8.0.4.1 (affected), < 7.2.3.1 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
EPSS Score
0.610%
GitHub Advisory
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | GitHub, Inc. · Vendor · USA |
| Reserved | 2026-03-17T22:16:36 |
| Published | 2026-03-23T23:24:55 |
| Last Updated | 2026-03-24T13:40:32 |
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