CVE-2019-5420: Debian Linux

Critical severity, CVSS 9.8. EPSS: 89.3% chance of exploitation in the next 30 days.

A remote code execution vulnerability in development mode Rails <5.2.2.1, <6.0.0.beta3 can allow an attacker to guess the automatically generated development mode secret token. This secret token can be used in combination with other Rails internals to escalate to a remote code execution exploit.

Affected products

• Debian Debian Linux: version 8.0 only
• Fedoraproject Fedora: version 30 only
• Rubyonrails Rails: before 5.2.2.1 (fixed in 5.2.2.1); version 6.0.0 only

Published 2019-03-27. Last modified 2026-06-17.