CVE
CVE-2021-21703
| CVE ID |
CVE-2021-21703
|
|---|---|
| CVSS Score |
7.0
|
| Operating System | |
| Affected Versions | |
| Patched Versions |
php-5.4.16-48_ol003.el7
|
| Patch Date |
|
| Last Updated Date | |
| Vector String |
Additional Information
OL CVE Issue Summary:
With PHP-FPM, a low-privilege process can read and write an array of pointers used by the main process (running as root), through shared memory. An attacker can leverage this problem to change a 32-bit integer from zero to one in the main process's memory, or clear a memory region. By leveraging the primitive multiple times, it is possible to reach another bug, make the main process execute code, and thus escalate privileges.
The pointers in the SHM have been present starting with the very first implementation (PHP 5.3.7).
This was addressed by converting `scoreboard->procs` to an array of scoreboards (no pointers anymore) and making sure `scoreboard->nprocs` only gets used by workers.