CVE-2026-33174

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

HIGH
7.5
CVSS Score
Published: March 23, 2026 at 11:24 PM UTC
Updated: June 17, 2026 at 10:37 AM UTC
2 products affected across 2 vendorsRailsActive Storage

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 7.2.3.18.0.0 ≤ v < 8.0.4.18.1.0 ≤ v < 8.1.2.1
v < 7.2.3.1v < 8.0.4.1v < 8.1.2.1
Affected range stops below 7.2.3.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 8.0.4.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 8.1.2.1, so it looks safe — our inference, not a vendor statement

References (7)

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-789

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