[CIVN-2026-0393] Arbitrary file read Vulnerability in Ruby on Rails Active Storage

By Published On: August 6, 2026

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Arbitrary file read Vulnerability in Ruby on Rails Active Storage


Indian – Computer Emergency Response Team (https://www.cert-in.org.in)


Severity Rating: CRITICAL


Software Affected


Rails version prior to 7.2.3.2

Rails version 8.0.0 or higher and prior to 8.0.5.1

Rails version 8.1.0 or higher and prior to 8.1.3.1

Overview


A vulnerability has been reported in Ruby on Rails Active Storage which could allow an unauthenticated remote attacker to read arbitrary files from the server and subsequently perform Remote Code Execution (RCE).


Target Audience:

All organizations and individuals using Ruby on Rails Active Storage with the libvips library enabled.


Risk Assessment:

High risk of unauthorized disclosure of sensitive files, secrets, and credentials, potentially leading to Remote Code Execution (RCE) and complete system compromise.


Impact Assessment:

High impact on Confidentiality, Integrity and Availability of the system.


Description


Ruby on Rails is a server-side web application framework written in Ruby. Active Storage is the Rails component used to upload, store, and process files.


This vulnerability exists Ruby on Rails because active Storage does not disable libvips operations that are considered unsafe when processing untrusted content. An unauthenticated remote attacker can exploit this vulnerability by uploading specially crafted image files.


Successful exploitation of this vulnerability could allow an attacker to read arbitrary files from the server. Exposure of sensitive information may subsequently lead to Remote Code Execution.


Solution


Apply appropriate Updates and steps as mentioned by the vendor:

https://github.com/rails/rails/security/advisories/GHSA-xr9x-r78c-5hrm



Vendor Information


 

https://github.com/rails/rails/security/advisories/GHSA-xr9x-r78c-5hrm


References


 

https://github.com/rails/rails/security/advisories/GHSA-xr9x-r78c-5hrm


CVE Name

CVE-2026-66066




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Thanks and Regards,

CERT-In


Incident Response Help Desk

e-mail: incident@cert-in.org.in

Phone: +91-11-22902657

Toll Free Number: 1800-11-4949

Toll Free Fax : 1800-11-6969

Web: http://www.cert-in.org.in

PGP Fingerprint: A768 083E 4475 5725 B81A A379 2156 C0C0 B620 D0B4

PGP Key information:

https://www.cert-in.org.in/s2cMainServlet?pageid=CONTACTUS


Postal address:

Indian Computer Emergency Response Team (CERT-In)

Ministry of Electronics and Information Technology

Government of India

Electronics Niketan

6, C.G.O. Complex

New Delhi-110 003

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