Vulnerabilities in data deserialization ( unserialize() ), buffer overflows in string handling, or flaws within third-party extensions allow attackers to inject malicious payloads.
Many vulnerabilities discovered in the PHP 5.x engine since 2019 remain unpatched in 5.6.40, including potential Remote Code Execution (RCE) and Denial of Service (DoS) vectors. Vulnerability Database Resources
The multibyte string component within PHP 5.6.40 is highly susceptible to critical heap-based buffer overflows.
If you are asking about , you are looking at the final, now obsolete release of PHP 5.6 from January 10, 2019. If "5640" refers to a version string like 5.6.4.0 (an old alpha), that version has even more unpatched flaws. This post assumes the former, as it is the more common legacy system reference. php version 5640 vulnerabilities link
| CVE ID | Severity | Description | Link | |--------|----------|-------------|------| | | Critical (9.8) | Remote Code Execution via env_path_info under specific FPM configurations. | NVD Link | | CVE-2020-7063 | High (7.5) | File upload $_FILES array injection leading to denial of service. | NVD Link | | CVE-2020-7060 | High (7.5) | mb_strpos() & mb_strrpos() may cause a heap-use-after-free. | NVD Link | | CVE-2019-11046 | Medium (6.1) | bcmath function bypass of safe_bin checks. | NVD Link |
If you need to analyze a specific system, please let me know:
The only permanent resolution to EOL vulnerabilities is migrating to a modern, actively supported version of PHP (such as PHP 8.x). Modern versions offer robust cryptographic primitives, strict type safety, and massive performance improvements. If you are asking about , you are
🔗 This page is the best single reference for all CVEs that affect 5.6.40.
(most authoritative)
What and version is hosting your PHP 5.6.40 environment? | CVE ID | Severity | Description |
Because PHP 5.6.40 is end-of-life (EOL), it remains vulnerable to multiple critical issues disclosed since its final release, including: CVE-2024-4577 (Critical - CVSS 9.8):
Some notable CVEs that affect 5.6.40:
Ensure that all application functionalities work correctly under the new PHP version. Why Upgrade to PHP 8.x?
from CVE Details shows many more critical issues (RCE, SQL injection via PDO, path traversal, etc.).