Vulnerability Report

CVE-2026-66066

RCE

Title: Arbitrary File Read and Potential RCE in Active Storage

Arbitrary File Access

Proof Of Concept

PoC Available for CVE-2026-66066

CWE Category CWE-1188

Published Date Jul 30, 2026

Modified Date Aug 05, 2026

Exploit Status Available

Score 9.5 CVSS v4.0

Exploit Probability (EPSS)

1.77%

Vulnerability Summary

CVE-2026-66066: Action Pack is a framework for handling and responding to web requests. In versions prior to 7.2.3.2, 8.0.5.1 and 8.1.3.1, Active Storage does not disable libvips operations marked unsafe for untrusted content, allowing a crafted upload to invoke such an operation. Consuming applications are affected when configured to use libvips and accept image uploads from untrusted users. An unauthenticated attacker may exploit this behavior to read arbitrary files accessible to the Rails process, including environment variables and application secrets. Exposure of credentials such as secret_key_base or external-service tokens may enable remote code execution or lateral movement. This issue has been fixed in versions 7.2.3.2, 8.0.5.1 and 8.1.3.1.

Impacted Vendors

Analysis in Progress...

Reference Links

https://github.com/rails/rails/commit/1c01bb587206ee6eb0e1179c2cef96a6a47acb1e https://github.com/rails/rails/commit/349e7a5d5b4b715af1e416db824f3c078a7d59e5 https://github.com/rails/rails/commit/d79b7f4aa17dec8ce4960fef05733c8c0c7ef49a https://github.com/rails/rails/releases/tag/v7.2.3.2 https://github.com/rails/rails/releases/tag/v8.0.5.1 https://github.com/rails/rails/releases/tag/v8.1.3.1 https://github.com/rails/rails/security/advisories/GHSA-xr9x-r78c-5hrm https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activestorage/CVE-2026-66066.yml https://thehackernews.com/2026/07/critical-rails-flaw-could-let.html http://www.openwall.com/lists/oss-security/2026/07/29/9

CVSS v4.0

Source Entity [email protected]

Severity CRITICAL

9.5

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

N/A

RAW VECTOR

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-66066 Exploits & PoCs (Proof Of Concept)

GitHub https://github.com/Zer0SumGam3/CVE-2026-66066-POC

View Code

GitHub https://github.com/0xBlackash/CVE-2026-66066

View Code

GitHub https://github.com/paveg/rails-activestorage-vips-audit

View Code

GitHub https://github.com/rails/rails-forensics-CVE-2026-66066

View Code

GitHub https://github.com/HackSpeak/kindarails2shell-poc

View Code

GitHub https://github.com/HackSpeak/CVE-2026-66066

View Code

August 05, 2026 MODIFIED