CVE-2021-21703

Publication date 21 October 2021

Last updated 24 July 2024

Ubuntu priority

High

Why this priority?

Cvss 3 Severity Score

7.0 · High

Score breakdown

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.

Read the notes from the security team

Status

Package Ubuntu Release Status
php5 22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty
php7.0 22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial
14.04 LTS trusty Not in release
php7.2 22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Fixed 7.2.24-0ubuntu0.18.04.10
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
php7.4 22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute
Fixed 7.4.16-1ubuntu2.2
20.04 LTS focal
Fixed 7.4.3-4ubuntu2.7
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
php8.0 22.04 LTS jammy Not in release
21.10 impish
Fixed 8.0.8-1ubuntu0.1
21.04 hirsute Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
php8.1 22.04 LTS jammy
Not affected
21.10 impish Not in release
21.04 hirsute Not in release
20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release

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Notes

sbeattie

PEAR issues should go against php-pear as of xenial

Severity score breakdown

Parameter Value
Base score 7.0 · High
Attack vector Local
Attack complexity High
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H