CVE-2026-66066
Action Pack: Possible arbitrary file read and remote code execution in Active Storage variant processing
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | Critical9.5 | 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 |
| NVDNVD · Awaiting Analysis | 4.0 | Critical9.5 | 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 |
- EPSS (exploitation in 30 days)
- 30.1% · top 1.8% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.5.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- RubyGemsactivestorageGHSA-xr9x-r78c-5hrm (opens in a new tab)
References (13)
- https://github.com/rails/rails/security/advisories/GHSA-xr9x-r78c-5hrm (opens in a new tab)x_refsource_CONFIRM
- https://github.com/rails/rails/commit/1c01bb587206ee6eb0e1179c2cef96a6a47acb1e (opens in a new tab)x_refsource_MISC
- https://github.com/rails/rails/commit/349e7a5d5b4b715af1e416db824f3c078a7d59e5 (opens in a new tab)x_refsource_MISC
- https://github.com/rails/rails/commit/d79b7f4aa17dec8ce4960fef05733c8c0c7ef49a (opens in a new tab)x_refsource_MISC
- https://github.com/rails/rails/releases/tag/v7.2.3.2 (opens in a new tab)x_refsource_MISC
- https://github.com/rails/rails/releases/tag/v8.0.5.1 (opens in a new tab)x_refsource_MISC
- https://github.com/rails/rails/releases/tag/v8.1.3.1 (opens in a new tab)x_refsource_MISC
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activestorage/CVE-2026-66066.yml (opens in a new tab)x_refsource_MISC
- https://thehackernews.com/2026/07/critical-rails-flaw-could-let.html (opens in a new tab)x_refsource_MISC
- http://www.openwall.com/lists/oss-security/2026/07/29/9 (opens in a new tab)
- https://ethiack.com/info-hub/research/kindarails2shell-rails-rce-cve-2026-66066 (opens in a new tab)
- http://www.openwall.com/lists/oss-security/2026/08/01/6 (opens in a new tab)
- https://github.com/rails/rails-forensics-CVE-2026-66066 (opens in a new tab)exploit
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-xr9x-r78c-5hrm (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-66066)Record last updated .