RCE in Zabbix

CVE-2026-23920

Host and event action script input is validated with a regex (set by the administrator), but the validation runs in multiline mode. If ^ and $ anchors are used in user input validation, an injected newline lets authenticated users bypass the check and inject shell commands.

Vulnerability class: Command Injection (OS Command Injection)

EPSS: 0.002 (16.3th percentile) — read the EPSS interpretation.