Ubuntu update for php5
| Risk | Low |
| Patch available | YES |
| Number of vulnerabilities | 1 |
| CVE-ID | CVE-2021-21703 |
| CWE-ID | CWE-787 |
| Exploitation vector | Local |
| Public exploit | Public exploit code for vulnerability #1 is available. |
| Vulnerable software |
Ubuntu Operating systems & Components / Operating system php7.4-fpm (Ubuntu package) Operating systems & Components / Operating system package or component php5-fpm (Ubuntu package) Operating systems & Components / Operating system package or component php7.0-fpm (Ubuntu package) Operating systems & Components / Operating system package or component php7.2-fpm (Ubuntu package) Operating systems & Components / Operating system package or component php8.0-fpm (Ubuntu package) Other |
| Vendor | Canonical Ltd. |
Security Bulletin
This security bulletin contains one low risk vulnerability.
1) Out-of-bounds write
EUVDB-ID: #VU57656
Risk: Low
CVSSv4.0: 7.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]
CVE-ID: CVE-2021-21703
CWE-ID:
CWE-787 - Out-of-bounds write
Exploit availability: No
DescriptionThe vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists in the way PHP handles shared memory access, when using PHP FPM SAPI with main FPM daemon process running as root and child worker processes running as lower-privileged users. A child process can access shared memory with the main process and write to it. As a result, it is possible to cause the root process to conduct invalid memory reads and writes with root privileges. A local user can trigger an out-of-bounds write error and execute arbitrary code on the system with root privileges.
Update the affected package php5 to the latest version.
Vulnerable software versionsUbuntu: 14.04 - 21.10
php7.4-fpm (Ubuntu package): All versions
php8.0-fpm (Ubuntu package): All versions
php5-fpm (Ubuntu package): All versions
php7.0-fpm (Ubuntu package): All versions
php7.2-fpm (Ubuntu package): All versions
CPE2.3- cpe:2.3:o:canonical:ubuntu:14.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:16.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:18.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:20.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:21.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:21.10:*:*:*:*:*:*:*
- cpe:2.3:a:canonical:php7.4-fpm:*:*:*:*:*:ubuntu:*:*
- cpe:2.3::canonical:php8.0-fpm_ubuntu_package:*:*:*:*:*:*:*:*
- cpe:2.3:a:canonical:php5-fpm:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:a:canonical:php7.0-fpm_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:a:canonical:php7.2-fpm_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-5125-1
Q & A
Can this vulnerability be exploited remotely?
No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.
