CVE-2021-21703

PHP-FPM memory access in root process leading to privilege escalation

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.

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We have discovered 1,010,879 live websites that are affected by CVE-2021-21703.

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Distribution by Website Rank

The diagram provides a graphic representation of the correlation between the occurrence of CVE-2021-21703 and the relative popularity of websites