CVE-2019-12522: Squid-Cache Squid

Medium severity, CVSS 4.5. EPSS: 0.3% chance of exploitation in the next 30 days.

An issue was discovered in Squid through 4.7. When Squid is run as root, it spawns its child processes as a lesser user, by default the user nobody. This is done via the leave_suid call. leave_suid leaves the Saved UID as 0. This makes it trivial for an attacker who has compromised the child process to escalate their privileges back to root.

Affected products

• Squid-Cache Squid: up to and including 4.7

Published 2020-04-15. Last modified 2026-06-17.