PHP version 5.6.40, released in 2018, is one such version that has reached its EOL. This version, like many others before it, had its share of vulnerabilities. Some of the notable vulnerabilities found in PHP 5.6.40 include:
Securing Legacy Systems: A Deep Dive into PHP 5.6.40 Vulnerabilities
Prior versions of PHP 5.6 up to 5.6.40 contain severe flaws. These issues allow unauthenticated attackers to trigger out-of-bounds reads, cause memory corruption, or execute code remotely. The official details can be tracked in the PHP 5 ChangeLog . 1. Multibyte String Vulnerabilities (mbstring)
: Red Hat Enterprise Linux (RHEL) and CloudLinux provide paid extended lifecycle support lifespans, backporting critical security fixes directly into their custom packages. Step 3: Deploy a Web Application Firewall (WAF) php version 5640 vulnerabilities link
High. Application downtime and potential data leakage. 3. Memory Corruption in PHAR Applications CVE Identifier: CVE-2019-11036
: By uploading a specifically crafted image or file file, an attacker can corrupt the heap memory, causing the server process to crash (Denial of Service) or execute shellcode with the privileges of the web server daemon ( www-data or apache ). 3. OpenSSL Dependency Vulnerabilities
Organized by MITRE, this database provides direct identification numbers for specific flaws. Review updates on the CVE Official Website. PHP version 5
However, some long-term support (LTS) vendors, such as , have continued to backport security fixes to this legacy version. While these updates address specific, known vulnerabilities, they do not transform PHP 5.6 into a secure, modern platform. Your code is still running on a foundation that is fundamentally outdated.
The multibyte string component ( mbstring ) contains multiple heap buffer over-read flaws within its regex processing functions. Functions handling multibyte tokenizing ( fetch_token ) or structural compilation ( compile_string_node ) fail to check string lengths properly. An attacker submitting a crafted multibyte string sequence can cause the PHP interpreter to leak system memory structures past allocated boundaries. 3. PHAR Extension Directory Traversals (CVE-2019-9021)
| Source | Link | Purpose | | :--- | :--- | :--- | | | https://www.php.net/ChangeLog-5.php#5.6.40 | The primary source for all bugs and security fixes included in the official 5.6.40 release. | | Official Release Announcement | https://www.php.net/releases/5_6_40.php | Official announcement from the PHP Group, noting it's a security release and the final planned release of the branch. | | NVD (NIST National Vulnerability Database) | https://nvd.nist.gov/ | Search for any CVE number (e.g., CVE-2019-9020) for detailed analysis, CVSS scores, and known exploits. | | Debian LTS Security Tracker | https://wiki.debian.org/LTS | For users on Debian 8 "Jessie", this is the source for backported security patches applied to their php5 packages. | | CVE Details (by CVE ID) | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-[YEAR]-[ID] | Direct link to the official CVE record for a specific vulnerability (e.g., https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-9020 ). | CVE-2019-9020) for detailed analysis
PHP 5.6.40 is considered "End of Life" (EOL). This means the PHP development team no longer provides security patches, bug fixes, or support. Every new vulnerability discovered since 2019 remains unpatched in this version.
If you can tell me what CMS (like WordPress) or framework (like Laravel) your site uses, I can provide a more specific checklist for your upgrade process. PHP 5.6: Why you should upgrade - Influential Software