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.
Early warning: exploitation observed
- Exploitation observed since Aug 25, 2026
- Not yet in the official CISA catalogue
- First attack observed 25 days after disclosure
- Confirmed by sensors, not only by reports
Source: VulnCheck KEV · Sep 13, 2026 Sep 3, 2026 Aug 31, 2026 Aug 31, 2026 Aug 25, 2026
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