Active Model in Ruby on Rails 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, and 5.x before 5.0.0.beta1.1 supports the use of instance-level writers for class accessors, which allows remote attackers to bypass intended validation steps via crafted parameters.
Severity
CVSS 3.1
5.3 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS
7.2% chance of exploitation in the next 30 days; higher than 94% of CVEs (scores of 2026-10-31)