#VU21220 Race condition in PHP - CVE-2019-9637

Vulnerability identifier: #VU21220

Vulnerability risk: Low

CVSSv4.0: 1.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2019-9637

CWE-ID: CWE-362

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
PHP
Universal components / Libraries / Scripting languages

Vendor: PHP Group

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition when renaming files on the system, as the rename() PHP function temporary creates files with weak privileges. A local user can exploit this behavior to gain access to sensitive information.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

PHP: 7.1.0 - 7.1.26, 7.2.0 - 7.2.15, 7.3.0alpha1 - 7.3.2

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External links
https://bugs.php.net/bug.php?id=77630

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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.