CVE-2021-21703

score

<0.1

cvss

7.8

epss

1.4%

published

2021-10-25

kev added

—

first seen

2026-10-21

PHP versions 7.3.x up to 7.3.31, 7.4.x below 7.4.25, and 8.0.x below 8.0.12 contain a privilege escalation caused by shared memory access in PHP FPM when main process runs as root and child processes run as lower-privileged users, letting local attackers escalate privileges, exploit requires local access to PHP FPM processes.