Vulnerability Intelligence Report
Action Pack: Possible arbitrary file read and remote code execution in Active Storage variant processing
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.
No Active Exploit Signals
CVSS Base Score
9.5
CRITICAL
EPSS Probability:1.70%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
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Authentication
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Weaponization
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SSVC Action
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Weaknesses (CWE)
CWE-1188 ↗CWE-1188: Insecure Default Initialization of Resource
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| rails | rails | < 7.2.3.2 (affected), >= 8.0.0.beta1, < 8.0.5.1 (affected), >= 8.1.0.beta1, < 8.1.3.1 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
EPSS Score
1.701%
GitHub Advisory
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | GitHub, Inc. · Vendor · USA |
| Reserved | 2026-07-23T23:25:28 |
| Published | 2026-07-30T18:32:11 |
| Last Updated | 2026-08-05T13:46:21 |
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