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Critical Rails Flaw Could Let Unauthenticated Attackers Read Server Files via Image Uploads

medthehackernewsPublished 2026-07-29

Ruby on Rails has released fixes for a critical Active Storage vulnerability that could let unauthenticated attackers read arbitrary files from application servers through crafted image uploads.

Tracked as CVE-2026-66066 (CVSS score: 9.5), the flaw can expose the Rails process environment and secrets such as secret_key_base, the Rails master key, database passwords, cloud storage credentials,

MITRE ATT&CK techniques

CredentialsT1589.001

Indicators of compromise

CVE-2026-66066cve

Original source: https://thehackernews.com/2026/07/critical-rails-flaw-could-let.html