CVE-2026-66066
Action Pack: Possible arbitrary file read and remote code execution in Active Storage variant processing
Description
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.
INFO
Published Date :
July 30, 2026, 7:18 p.m.
Last Modified :
July 30, 2026, 8:18 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-66066
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Update Action Pack to version 7.2.3.2 or higher.
- Update Action Pack to version 8.0.5.1 or higher.
- Update Action Pack to version 8.1.3.1 or higher.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-66066.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-66066 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-66066
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-66066 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-66066 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 30, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-66066', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-30T19:16:09.405495Z'} -
New CVE Received by [email protected]
Jul. 30, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'rails', 'product': 'rails', 'versions': [{'status': 'affected', 'version': '< 7.2.3.2'}, {'status': 'affected', 'version': '>= 8.0.0.beta1, < 8.0.5.1'}, {'status': 'affected', 'version': '>= 8.1.0.beta1, < 8.1.3.1'}]}] Added Description 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. Added CVSS V4.0 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 Added CWE CWE-1188 Added Reference https://github.com/rails/rails/commit/1c01bb587206ee6eb0e1179c2cef96a6a47acb1e Added Reference https://github.com/rails/rails/commit/349e7a5d5b4b715af1e416db824f3c078a7d59e5 Added Reference https://github.com/rails/rails/commit/d79b7f4aa17dec8ce4960fef05733c8c0c7ef49a Added Reference https://github.com/rails/rails/releases/tag/v7.2.3.2 Added Reference https://github.com/rails/rails/releases/tag/v8.0.5.1 Added Reference https://github.com/rails/rails/releases/tag/v8.1.3.1 Added Reference https://github.com/rails/rails/security/advisories/GHSA-xr9x-r78c-5hrm Added Reference https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activestorage/CVE-2026-66066.yml Added Reference https://thehackernews.com/2026/07/critical-rails-flaw-could-let.html -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Jul. 30, 2026
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2026/07/29/9