5640 Vulnerabilities Verified - Php Version

The attacker constructs a serialized string or specific nested array that tricks PHP's reference counter into miscounting references to an object.

PHP Version 5.6.40: Verified Vulnerabilities and the Risks of Outdated Code php version 5640 vulnerabilities verified

Outdated SSL/TLS implementations within the PHP 5.6 core do not support modern encryption standards. Risk Analysis Threat Level Description Critical Full System Compromise Unauthorized access to the underlying OS. High Data Breach Potential theft of database credentials and user info. High Compliance Failure The attacker constructs a serialized string or specific

To verify if your system is vulnerable, security engineers often run Nessus scans which will flag the presence of php 5.6.x and immediately list these CVEs. Alternatively, a simple check of the PHP info page ( phpinfo(); ) will reveal the exact build version. High Data Breach Potential theft of database credentials

A heap-based buffer over-read in PHAR extension reading functions.

PHP 5.6.40 is a security liability. With verified vulnerabilities allowing for full system compromises, continuing to use it in 2026 is extremely risky. The security, performance, and compliance benefits of upgrading to PHP 8.x make the transition necessary for any serious web project. I can help you:

Security researchers and scanner plugins, such as the Nessus plugin ID 121602, have identified that all PHP versions running 5.6.x prior to 5.6.40 are affected by multiple critical flaws. These vulnerabilities span several components of the language and server stack.