CVE-2021-21703

high

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.

References

https://bugs.php.net/bug.php?id=81026

https://www.debian.org/security/2021/dsa-4993

https://www.debian.org/security/2021/dsa-4992

http://www.openwall.com/lists/oss-security/2021/10/26/7

https://lists.debian.org/debian-lts-announce/2021/10/msg00021.html

https://lists.fedoraproject.org/archives/list/[email protected]/message/PBM3KKB3RY2YPOKNMC4HIH7IH3T3WC74/

https://lists.fedoraproject.org/archives/list/[email protected]/message/JO5RA6YOBGGGKLIA6F6BQRZDDECF5L3R/

https://lists.fedoraproject.org/archives/list/[email protected]/message/6PZVLICZUJMXOGWOUWSBAEGIVTF6Y6V3/

https://security.netapp.com/advisory/ntap-20211118-0003/

https://www.oracle.com/security-alerts/cpujan2022.html

https://www.oracle.com/security-alerts/cpuapr2022.html

https://security.gentoo.org/glsa/202209-20

Details

Source: MITRE

Published: 2021-10-25

Updated: 2022-09-29

Type: CWE-787

Risk Information

CVSS v2

Base Score: 6.9

Vector: AV:L/AC:M/Au:N/C:C/I:C/A:C

Impact Score: 10

Exploitability Score: 3.4

Severity: MEDIUM

CVSS v3

Base Score: 7

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Impact Score: 5.9

Exploitability Score: 1

Severity: HIGH