Active Storage has possible arbitrary file read and remote code execution in Active Storage variant processing
Critical vendor advisory
CVE-2026-66066
Summary
Active Storage has possible arbitrary file read and remote code execution in Active Storage variant processing
Why it matters
GitHub has published a reviewed security advisory for activestorage. Prioritize it with other application dependency updates.
Operator check
Check whether activestorage is present in application dependency manifests, lockfiles, or build images. Review the GitHub advisory and upgrade to a patched version where available. CVSS score: 9.5.
Sources
PatchBrief uses public sources. It does not scan environments, verify exposure, or replace vendor guidance.