Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2021-21703

Disclosure Date: October 18, 2021 •
CVE-2021-21703 CVSS v3 Base Score: 7.0
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

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.

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CVSS V3 Severity and Metrics
Base Score:
7.0 High
Impact Score:
5.9
Exploitability Score:
1
Vector:
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
High
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
PHP 7.3.31
PHP 7.4.25
PHP 8.0.12
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown

Vendors

  • debian,
  • fedoraproject,
  • netapp,
  • oracle,
  • php

Products

  • clustered data ontap -,
  • communications diameter signaling router,
  • debian linux 10.0,
  • debian linux 11.0,
  • debian linux 9.0,
  • fedora 33,
  • fedora 34,
  • fedora 35,
  • php
Technical Analysis