CVE-2026-66066
Description
A flaw was found in Active Storage, a component of Action Pack. An unauthenticated attacker can exploit this vulnerability by crafting a malicious file upload. This allows the attacker to invoke unsafe libvips operations, leading to the ability to read arbitrary files on the system including sensitive environment variables and application secrets. The exposure of these credentials could enable remote code execution or lateral movement within the affected system.
Statement
This Important flaw in Active Storage allows unauthenticated remote attackers to read arbitrary files and potentially achieve remote code execution. This occurs in applications configured with libvips as the Active Storage variant processor (a default since Rails 7.0) that accept untrusted image uploads.
Red Hat Satellite: The Active Storage engine is explicitly commented out and disabled at runtime across all Satellite/Foreman builds. Furthermore, libvips dependencies are not shipped marking Red Hat Satellite as Not Affected.
Red Hat 3scale: Neither the libvips binary nor its shared libraries are present in any 3scale container image, hence 3scale product is not affected.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.9 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Changed | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | Low | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
Red Hat CVSS v3 Score Explanation
Mapped from upstream CVSS v4.0 (9.5). AT:P maps to AC:H - exploitation requires libvips as image processor (default since Rails 7.0) and untrusted image uploads accepted.
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
Arbitrary code execution is possible if an uploaded file is interpreted and executed as code by the recipient. This is especially true for web-server extensions such as .asp and .php because these file types are often treated as automatically executable, even when file system permissions do not specify execution. For example, in Unix environments, programs typically cannot run unless the execute bit is set, but PHP programs may be executed by the web server without directly invoking them on the operating system.
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