Home/CVE/Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, a
CVE

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, a

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.

HIGH · CVSS 7.5 EPSS 0.00024
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules1 YARA rules0
⬡

Weakness Classification

CWE-789Memory Allocation with Excessive Size Value
▤

Affected Products & Versions

3
rubyonrails rails< 7.2.3.1
rubyonrails rails>= 8.0.0 and < 8.0.4.1
rubyonrails rails>= 8.1.0 and < 8.1.2.1
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
RubyGems activestorage MODERATE fixed in 8.1.2.1
◈

Sigma Hunt Rules

1
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
productmediumRuby on Rails Framework Exceptions
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD24 Mar 2026 · 12:16 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

7
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/rails/rails/commit/2cd933c366b777f873d4d590127da2f4a25e4ba5Patch
https://github.com/rails/rails/commit/42012eaaa88dfc7d0030161b2bc8074a7bbce92aPatch
https://github.com/rails/rails/commit/8159a9c3de3f27a2bcf2866b8bf9ceb9075e229bPatch
https://github.com/rails/rails/releases/tag/v7.2.3.1Release Notes
https://github.com/rails/rails/releases/tag/v8.0.4.1Release Notes
https://github.com/rails/rails/releases/tag/v8.1.2.1Release Notes
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