OPcache is a PHP extension that stores compiled bytecode in shared memory. By avoiding repeated parsing and compilation of PHP scripts, it can reduce processing time and server load. It is commonly enabled in production PHP environments.
Because OPcache sits within the PHP runtime, it is part of the software defenders need to inventory and keep updated-not a substitute for patching PHP itself. In security incidents, a flaw involving OPcache or its interaction with other runtime components may contribute to memory corruption or other vulnerabilities. After updating PHP, administrators should ensure the running workers have reloaded the patched runtime and that OPcache is using the corrected code.