Php Version 5.6.40 Vulnerabilities [updated]

If you absolutely cannot upgrade your code, use a service like CloudLinux or Ubuntu ESM , which provides backported security patches for EOL versions.

| CVE ID | Severity | Description | |--------------|----------|-------------| | CVE-2022-31625 | High | PHP-FPM local RCE via environment variable poisoning. | | CVE-2022-31626 | High | MySQL password hash overflow in mysqli . | | CVE-2021-21708 | Critical | filter_var() with FILTER_VALIDATE_URL double-free RCE. | | CVE-2020-7068 | High | mb_strcut() illegal string offset RCE. | | CVE-2020-7060 | Medium | mbfl_filt_conv_big5_wchar heap use-after-free. |

If you absolutely cannot upgrade today, implement these draconian measures: php version 5.6.40 vulnerabilities

When security researchers disclose vulnerabilities in modern PHP versions (currently 8.x), those flaws are often back-ported or checked against older versions. If a flaw exists in PHP 8.0 and is found to be present in the 5.6 codebase, the developers will patch PHP 8.0, but PHP 5.6.40 will remain vulnerable forever. Hackers actively scan for these disclosures, checking if they apply to legacy systems, creating an open door for exploitation.

Its status as an End-of-Life release means it contains hundreds of unpatched, publicly known vulnerabilities, including critical remote code execution flaws. Continued use exposes organizations to predictable and preventable security breaches. If you absolutely cannot upgrade your code, use

Beyond core PHP vulnerabilities, 5.6.40 suffers from its extensions being obsolete.

Security vendors often recommend "virtual patching" via Web Application Firewalls (WAFs). While a WAF (ModSecurity, CloudFlare, AWS WAF) can block known exploit signatures, it cannot fix logic flaws. Zero-day vulnerabilities still bypass WAFs. | | CVE-2021-21708 | Critical | filter_var() with

function (CVE-2016-10166) allowed unauthenticated remote attackers to cause unspecified system impacts. Heap-Based Buffer Overflow (GD Graphics Library): Improper calculation of buffer sizes in gdImageColorMatch