Known exploited · Rails
CVE-2019-5418: Rails Ruby on Rails Path Traversal Vulnerability
What it is
Rails Ruby on Rails contains a path traversal vulnerability in Action View. Specially crafted accept headers in combination with calls to `render file:` can cause arbitrary files on the target server to be rendered, disclosing the file contents.
- Vendor
- Rails
- Product
- Ruby on Rails
- Added to KEV
- July 7, 2025
- CISA due date
- July 28, 2025
- Ransomware use
- Unknown
What CISA requires
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Forensic triage
No
What to do now
- Find every instance of Ruby on Rails you run, including the forgotten ones, and check its version against the vendor advisory.
- Apply the vendor's fix or mitigation, before July 28, 2025 if you are bound by CISA's deadline, sooner if it faces the internet.
- Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
- Until every instance is patched, block the attack at the edge: a WAF in blocking mode stops path traversal attempts.
References
The Dome
Block it at the edge while you patch
The Dome's WAF runs the OWASP Core Rule Set in blocking mode and stops path traversal attempts before they reach your application.
See the DomeT Academy
Train the engineers who fix it
Security engineering on real hosts in the browser, every objective checked on the machine. The first two lessons of Linux 1 are free.
Start freeSource: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.