Debian update for php7.4



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
 Debian Linux
Operating systems & Components / Operating system

php7.4 (Debian package)
Operating systems & Components / Operating system package or component

Vendor Debian

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

Description

The 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.



Mitigation

Update php7.4 package to version 7.4.25-1+deb11u1.

Vulnerable software versions

Debian Linux: All versions

php7.4 (Debian package): before 7.4.25-1+deb11u1

CPE2.3 External links

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


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.



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