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

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vulnerabilities

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

Ruby on Rails released patches for a critical Active Storage vulnerability (CVE-2026-66066, CVSS 9.5) that allows unauthenticated attackers to read arbitrary server files through specially crafted image uploads. The flaw could expose sensitive data including environment variables, secret keys, database passwords, and cloud storage credentials stored on vulnerable application servers.

Why it matters: Rails application operators must apply patches immediately; any public-facing Rails application accepting image uploads is at risk of credential and secret exposure without authentication required.

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Correction

Correction recorded as of .

vulnerabilities

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

Ruby on Rails released patches for a critical Active Storage vulnerability (CVE-2026-66066, CVSS 9.5) that allows unauthenticated attackers to read arbitrary server files through specially crafted image uploads. The flaw could expose sensitive data including environment variables, secret keys, database passwords, and cloud storage credentials stored on vulnerable application servers.

Why it matters: Rails application operators must apply patches immediately; any public-facing Rails application accepting image uploads is at risk of credential and secret exposure without authentication required.

Source published
First seen by Cybersecurity Tracker

Source attribution

Glossary