CVE-2019-18409 — The ruby_parser-legacy (aka legacy) gem 1.0.0 for Ruby allows local privilege escalation because of world-writable files

Matched remediation archetype

Privilege escalation and unsafe privilege management

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

• Map service accounts, operating-system identities, roles, capabilities, impersonation, set-user transitions, and administrative helper paths.
• Determine whether untrusted users or lower-privilege processes can reach the affected transition or modify inputs it trusts.
• Review file, socket, registry, device, job, container, and cloud-role permissions used before and after privilege changes.

Remediate safely

• Apply the supported fix and redesign privileged operations as a minimal, authenticated, allowlisted interface.
• Drop privileges before processing untrusted input, verify the drop succeeds, and remove unnecessary roles, capabilities, and write permissions.
• Validate ownership and permissions at time of use and add explicit lower-to-higher privilege boundary tests.