VULNERABILITY INTELLIGENCE
CVE-2021-21703
CVSS score7.8 HIGH
EPSS probability1.43%
CISA KEVNot currently listed
Published2021-10-25
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Description
In PHP versions 7.3.x up to and including 7.3.31, 7.4.x below 7.4.25 and 8.0.x below 8.0.12, when running PHP FPM SAPI with main FPM daemon process running as root and child worker processes running as lower-privileged users, it is possible for the child processes to access memory shared with the main process and write to it, modifying it in a way that would cause the root process to conduct invalid memory reads and writes, which can be used to escalate privileges from local unprivileged user to the root user.
Weakness classification
- security@php.net: CWE-284
- nvd@nist.gov: CWE-787
Primary references
- security@php.net — Mailing List, Patch, Third Party Advisory
- security@php.net — Exploit, Issue Tracking, Patch, Vendor Advisory
- security@php.net — Mailing List, Third Party Advisory
- security@php.net
- security@php.net
- security@php.net
- security@php.net — Third Party Advisory
- security@php.net — Third Party Advisory
- security@php.net — Third Party Advisory
- security@php.net — Third Party Advisory
- security@php.net — Patch, Vendor Advisory
- security@php.net — Patch, Vendor Advisory