Php Version 5640 Vulnerabilities Link May 2026

PHP version 5.6.40 was the final release of the PHP 5.6 branch, serving as a "last stand" for security on an aging architecture. While its release on January 10, 2019, was meant to address the final known critical flaws, it also marked the official End of Life (EOL) for the entire PHP 5 series. The Story of PHP 5.6.40: The Final Patch

For years, PHP 5.6 was the backbone of the web, powering millions of WordPress sites and legacy enterprise applications. As the 2018 deadline for ending support approached, the developers released version 5.6.40 to close the remaining gaps. However, because it is now unsupported, any vulnerabilities discovered after its release remain unpatched for the general public. Key Vulnerabilities and Risks

While 5.6.40 itself was a security update, the environment it lives in is fraught with risks:

Inherited Flaws: Systems running 5.6.4x or earlier are often flagged for multiple vulnerabilities including:

Integer Underflow/Overflow: Flaws in functions like gd_interpolation.c could allow remote attackers to cause unspecified impacts through crafted image data.

Memory Corruption: Older versions of 5.6 were susceptible to heap-based buffer overflows and dangling pointer errors that could lead to Remote Code Execution (RCE).

The "Shadow" Vulnerabilities: Because official support ended in December 2018, no new CVEs are officially "fixed" by the PHP team for this version. This makes the version "low hanging fruit" for attackers who look for sites still running this legacy code.

Third-Party Dependency Risks: Modern vulnerabilities in shared libraries, such as the 24-year-old GLIBC bug (iconv buffer overflow), can still compromise PHP applications even if the PHP engine itself hasn't changed. Why Upgrading is Essential

Staying on PHP 5.6.40 is widely considered a major security risk today. Security experts at Influential Software and TuxCare emphasize that:

PHP 5.6.40, which reached end-of-life on December 31, 2018, is vulnerable to numerous security risks, including heap-based buffer overflows (CVE-2019-9023, CVE-2019-6977) and arbitrary code execution, due to a lack of security patches. Continued use of this version poses significant compliance risks, such as violating PCI DSS and GDPR standards, while hindering performance compared to PHP 8.x. For more information on the release, see the PHP 5.6.40 Release Announcement endoflife.date PHP | endoflife.date

PHP version 5.6.40 was released on January 10, 2019, as a final security release for the PHP 5.6 branch. Because PHP 5.6 reached official End of Life (EOL) shortly after this release, it no longer receives official security updates, leaving it vulnerable to any flaws discovered after that date. Core Vulnerabilities Addressed by Upgrading to 5.6.40

Users running versions prior to 5.6.40 are affected by several critical vulnerabilities that this specific release was designed to patch:

Heap-based Buffer Over-read (CVE-2019-9020 / CVE-2019-9024): Flaws in the xmlrpc_decode function could allow a remote attacker to cause a system compromise or read memory outside of allocated areas via specially crafted requests.

PHAR Extension Memory Disclosure (CVE-2019-9021): Improper memory operations in PHAR reading functions could allow an attacker to disclose sensitive information by persuading a user to parse a crafted filename.

Buffer Overflows in mbstring (CVE-2019-9023): Regular expression functions in the mbstring component were found to have vulnerabilities that could lead to a complete system compromise through crafted multibyte sequences.

Integer Underflow (CVE-2016-10166): An issue in the _gdContributionsAlloc function could lead to unspecified remote impact. Risks of Remaining on 5.6.40

Since 5.6.40 is the last scheduled release, it remains vulnerable to newer threats discovered after 2019, such as:

Surviving PHP 7 End of Life: Best Practices for a Secure Transition

I understand you're looking for vulnerability information related to PHP version 5.6.40. Here are the most reliable sources:

Recommendations

Upgrade to a newer version of PHP: PHP 5.6.40 is an outdated version, and it's highly recommended to upgrade to a newer version, such as PHP 7.4 or later, which has many security patches and improvements.
Enable security features: Make sure to enable security features like display_errors set to Off and error_reporting set to E_ALL in your php.ini file.
Use a web application firewall (WAF): Consider using a WAF to help protect against common web attacks.

What Does "End-of-Life" Mean for Security?

When software reaches EOL, the developers stop releasing updates—period. This means:

No Bug Fixes: If a function breaks in a new OS environment, it stays broken.
No Security Patches: If a hacker discovers a zero-day vulnerability today, there will never be a patch released for PHP 5.6.40.
Compliance Issues: Running EOL software almost universally violates security standards like PCI-DSS, HIPAA, and GDPR.

Conclusion: The Only Safe Link Is the Upgrade Path

If you arrived here looking for "php version 5640 vulnerabilities link" , you now have a comprehensive set of URLs:

CVE Details for 5.6.40 – The master list of flaws.
NVD Search for 5.6.40 – Official metrics.
PHP EOL Policy – The legal notice that your version is dead.
PHP 8.3 Migration Guide – The exit strategy.

Do not fall into the trap of simply monitoring the "vulnerabilities link." The link is a tombstone. Every month that you serve PHP 5.6.40 to the public internet, you are betting that no attacker will click the exploit link before you click the upgrade button.

Action item: Run php -v today. If you see 5.6.40, treat it as a critical incident. Your security audit links start here, but they must end with a migration plan.

Disclaimer: This article is for educational and security auditing purposes. Always test upgrades in a staging environment. As of 2026, PHP 5.6.40 should never be used in production.

PHP 5.6.40 in a production environment is a major security risk because it reached its End of Life (EOL) on December 31, 2018

. Since that date, the official PHP development team has provided no security updates or bug fixes php version 5640 vulnerabilities link

for this version, leaving it permanently exposed to any vulnerabilities discovered over the last several years. Critical Vulnerabilities in PHP 5.6.40

While PHP 5.6.40 was the final security release for the 5.6 branch, it is still susceptible to numerous unpatched flaws and inherited issues. Key risks include: Remote Code Execution (RCE): Flaws in core extensions like ext/session

can allow attackers to execute arbitrary code on your server through type confusion or use-after-free issues. Heap-based Buffer Over-reads: Vulnerabilities in the reading functions and extension (e.g., CVE-2019-9021 CVE-2019-9023

) can be exploited to read sensitive memory or cause a complete system compromise. Integer Underflows and Overflows:

Improper implementation of memory operations in functions like gdImageColorMatch CVE-2019-6977

) can lead to unauthorized data access or application crashes. Out-of-Bounds Reads: xmlrpc_decode CVE-2019-9024

) can allow a hostile server to read data outside of allocated memory. Why You Must Upgrade

Staying on 5.6.40 is often referred to as "leaving your front door unlocked".

You're referring to PHP version 5.6.40, which has several known vulnerabilities. To address these concerns, I'll outline a feature that can help mitigate these issues.

Feature: "PHP Vulnerability Shield"

Description: A PHP module that provides an additional layer of security to prevent exploitation of known vulnerabilities in PHP 5.6.40. This module will:

Monitor and filter incoming requests: Analyze incoming requests for suspicious patterns and block requests that may be attempting to exploit known vulnerabilities.
Disable vulnerable functions: Identify and disable functions that are known to be vulnerable, preventing their use even if an attacker tries to exploit them.
Provide updates and patches: Offer a mechanism to easily apply security patches and updates to vulnerable functions, ensuring the system stays protected.

Key Components:

Vulnerability Database: A comprehensive database of known vulnerabilities in PHP 5.6.40, which will be used to identify and block suspicious requests.
Request Analyzer: A component that analyzes incoming requests and checks them against the vulnerability database.
Function Disabler: A feature that disables vulnerable functions to prevent exploitation.
Patch Manager: A tool that allows for easy application of security patches and updates.

Implementation:

Create a vulnerability database with a list of known vulnerabilities in PHP 5.6.40.
Develop a request analyzer that checks incoming requests against the vulnerability database.
Implement a function disabler that disables vulnerable functions.
Design a patch manager that allows for easy application of security patches and updates.

Example Code:

// Vulnerability Database
$vulnerabilityDB = [
    'function_name' => [
        'vulnerability_description',
        'exploit_pattern',
    ],
    // ...
];
// Request Analyzer
function analyzeRequest($request) 
    global $vulnerabilityDB;
    foreach ($vulnerabilityDB as $function => $vulnerability) 
        if (preg_match($vulnerability['exploit_pattern'], $request)) 
            // Block the request
            return false;
return true;
// Function Disabler
function disableVulnerableFunctions() 
    global $vulnerabilityDB;
    foreach ($vulnerabilityDB as $function => $vulnerability) 
        // Disable the function
        function_exists($function) && eval("unset($$function);");
// Patch Manager
function applyPatch($patch) 
    // Apply the patch
    // ...

Benefits:

Improved Security: The PHP Vulnerability Shield provides an additional layer of security, protecting against known vulnerabilities in PHP 5.6.40.
Easy Maintenance: The patch manager allows for easy application of security patches and updates, reducing the burden on system administrators.
Flexibility: The module can be easily updated to address new vulnerabilities and PHP versions.

This feature can be integrated into existing PHP applications, providing a robust security solution for PHP 5.6.40.

PHP version 5.6.40, released in January 2019, was the final security update for the PHP 5.6 branch and is now end-of-life (EOL). While it addressed several critical issues, it remains vulnerable to newer exploits discovered after its support ended. Core Vulnerabilities Addressed in PHP 5.6.40

The 5.6.40 release specifically fixed the following critical security flaws:

Buffer Overflows & Underflows: Fixed multiple heap-based buffer overflows in the mbstring extension (CVE-2019-9023) and an integer underflow in the gd graphics library (CVE-2016-10166).

Out-of-Bounds Reads: Resolved issues in the xmlrpc_decode function (CVE-2019-9020) and the PHAR extension (CVE-2019-9021) that could lead to memory disclosure.

Remote Code Execution (RCE): Addressed flaws that unauthenticated, remote attackers could exploit to compromise systems entirely. Post-Release Risks (EOL Status)

Because PHP 5.6.40 is no longer maintained, it is susceptible to vulnerabilities found in later versions of PHP that were never backported. A major example is CVE-2024-4577, a critical remote code execution flaw in PHP-CGI on Windows that impacts all legacy versions. Security Documentation & Papers

Official ChangeLog: The PHP 5 ChangeLog provides the definitive list of bugs fixed in the 5.6.40 release.

Vulnerability Databases: Detailed technical breakdowns of each CVE associated with this version can be found on CVE Details and Tenable.

Academic/Research Context: For a broader look at PHP security, papers like the USENIX study on SSRF-Defenses in PHP Applications discuss modern attack vectors that still affect legacy environments. PHP 5.6.x < 5.6.40 Multiple vulnerabilities. | Tenable® PHP version 5

Understanding PHP 5.6.40: Vulnerabilities and Risks Running PHP 5.6.40 in a modern production environment is a significant security risk. Released on January 10, 2019, version 5.6.40 was the final security release for the PHP 5.6 branch. Official security support for this branch ended on December 31, 2018.

Because this version is End-of-Life (EOL), any vulnerabilities discovered after its final release remain unpatched by the official PHP development team. Core Vulnerabilities in PHP 5.6.40

Although 5.6.40 was a "security release" intended to fix known issues, it remains susceptible to several critical flaws identified at the time of its release and many more discovered since.

I see you're looking for information on PHP version 5.6.40 vulnerabilities. Here's what I found:

PHP 5.6.40 Vulnerabilities:

PHP 5.6.40 is an older version of PHP, and as such, it has some known vulnerabilities. According to the PHP security team, PHP 5.6.40 has several fixed vulnerabilities. Here are a few:

CVE-2019-11045: A bug in the exif extension could lead to a crash or potentially allow an attacker to execute arbitrary code.
CVE-2019-11046: A bug in the mb_check_encoding function could lead to a crash or potentially allow an attacker to execute arbitrary code.
CVE-2019-11047: A bug in the iconv extension could lead to a crash or potentially allow an attacker to execute arbitrary code.

You can find more information on these vulnerabilities and their fixes on the official PHP website:

PHP 5.6.40 ChangeLog

Upgrade to a newer PHP version:

It's highly recommended to upgrade to a newer PHP version, such as PHP 7.4 or later, which includes many security fixes and improvements.

Links:

Please note that PHP 5.6.40 is an outdated version, and using it may expose your application to known security vulnerabilities. Upgrading to a newer PHP version is essential to ensure your application's security and stability.

PHP version 5.6.40 was the final security release for the PHP 5.6 branch. While its release in early 2019 fixed several critical issues, it is now officially End of Life (EOL) and has not received official security patches since late 2018. Critical Vulnerabilities Fixed in 5.6.40

Version 5.6.40 was primarily released to address the following critical and high-severity flaws found in earlier 5.6.x versions:

CVE-2019-9021 (Severity: 9.8 Critical): A heap-based buffer over-read in mbstring regular expression functions. A remote attacker could send crafted multibyte sequences to cause a system compromise or crash.

CVE-2019-9023 (Severity: 9.8 Critical): An out-of-bounds read error in the xmlrpc_decode function. Remote attackers could cause memory corruption or information disclosure via a hostile XML-RPC server.

CVE-2019-9020 (Severity: 7.5 High): A heap-based buffer over-read in PHAR reading functions. Attackers could exploit this via crafted file names to disclose sensitive information.

CVE-2019-9024 (Severity: 7.5 High): Another out-of-bounds read in xmlrpc_decode related to base64 decoding. Post-5.6.40 Risks

Because 5.6.40 is the final version of an unsupported branch, any vulnerabilities discovered after its release remain unpatched in official builds. Significant threats include: PHP 5.6: Why you should upgrade - Influential Software

PHP version 5.6.40 was released on January 10, 2019 , as a final security release for the 5.6 branch. While 5.6.40 itself addressed several issues, it has since reached its official End of Life (EOL)

and no longer receives security patches from the PHP development team.

Detailed lists of historical vulnerabilities and CVEs for this version can be found on CVE Details Blog Post: The Hidden Risk of PHP 5.6.40 in 2026 If you are still running PHP 5.6.40

, you are essentially driving a car with a 2019 inspection sticker—it might still run, but it’s no longer safe for the road.

As of April 2026, PHP 5.6.40 has been officially unsupported for over seven years. While it was intended to be the most secure version of the 5.6 series at the time of its release, the threat landscape has evolved drastically since then. Why "Final Security Release" is a Misnomer

When PHP 5.6.40 dropped in early 2019, it was the "last scheduled release". However, "final" doesn't mean "invulnerable." It simply means the PHP team stopped looking for bugs in that branch. Any vulnerability discovered since then—of which there have been many—remains in your environment. Critical Vulnerabilities at a Glance

Systems running PHP 5.6.40 or earlier are susceptible to several high-impact exploits: PHP PHP 5.6.40 security vulnerabilities, CVEs Upgrade to a newer version of PHP : PHP 5

This page lists vulnerability statistics for CVEs published in the last ten years, if any, for PHP » PHP » 5.6. 40 . CVE Details Unsupported Branches - PHP

PHP version 5.6.40 was released on January 10, 2019, as the final security release for the PHP 5.6 branch. While it addressed several critical security bugs at the time, it reached its official End of Life (EOL) on December 31, 2018, meaning it has not received official security updates or bug fixes for over seven years. Key Vulnerabilities in PHP 5.6.40

Although 5.6.40 was a "security release," it remains vulnerable to numerous exploits discovered after its EOL. Because the PHP project no longer maintains this branch, any vulnerability found since 2019 remains unpatched in official builds.

Heap-Based Buffer Over-reads (CVE-2019-9023): This critical vulnerability occurs in mbstring regular expression functions when they are supplied with invalid multibyte data. It can allow a remote attacker to compromise the target system.

PHAR Reading Issues (CVE-2019-9021): A heap-based buffer over-read in the PHAR extension may allow attackers to read memory past actual data while parsing filenames.

Integer Underflow (CVE-2016-10166): An issue in the _gdContributionsAlloc function in gd_interpolation.c can have unspecified impacts via unauthenticated remote attacks.

Exposed phpinfo() Page: While not a vulnerability in the code itself, many legacy 5.6.40 setups leave the phpinfo() page public, which discloses sensitive server information that aids in formulating Remote Code Execution (RCE) or Local File Inclusion (LFI) attacks. Security Risk Summary

Using PHP 5.6.40 in 2026 is considered high-risk. Automated scanners frequently identify hundreds of known vulnerabilities in environments running this version. Snyk - Vulnerability report for Docker php:5.6.40-apache

PHP version 5.6.40 was released on January 10, 2019 , as a final security update to address several critical bugs. Official security support for the entire PHP 5.6 branch ended on December 31, 2018

, meaning version 5.6.40 and all prior 5.6.x versions no longer receive official patches for newly discovered flaws. Critical Vulnerabilities in PHP 5.6.40

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):

A remote code execution (RCE) vulnerability that affects PHP running on Windows in CGI configurations. Attackers can bypass previous protections to execute arbitrary commands. Buffer Overflows & Underflows: CVE-2016-10166: An integer underflow in the gd_interpolation.c CVE-2019-6977: A heap-based buffer overflow in gdImageColorMatch Memory Corruption: CVE-2019-9020: A heap-based buffer over-read in xmlrpc_decode that can lead to system compromise. CVE-2019-9021:

A heap-based buffer over-read in the PHAR extension allowing attackers to read memory past actual data. Out-of-Bounds Reads: CVE-2019-9024: An out-of-bounds read error in xmlrpc_decode triggered by a hostile XMLRPC server. Regular Expression Vulnerabilities: CVE-2019-9023: Multiple heap-based buffer over-read instances in regular expression functions. Security Risks of Continued Use

As of 2026, running PHP 5.6.40 poses extreme risks to production environments: PHP Requirements - Knowledgebase - The Events Calendar

In the quiet, humming rows of a forgotten data center, a server named "Old Faithful" still ran a relic: PHP version 5.6.40. Released on January 10, 2019, this was the final curtain call for the PHP 5.6 branch, a version that had powered the web for years but was now officially unsupported and "End of Life".

For a long time, Old Faithful felt secure. After all, 5.6.40 was a "security release." It had been patched to fix multiple vulnerabilities that plagued earlier 5.6.x versions, including integer underflow, buffer overflows, and out-of-bounds read errors. It was the fortress built to withstand the dying days of an era.

But as years passed, the world outside changed. The CVD (Common Vulnerabilities and Exposures) database began to list new shadows:

Memory Corruption: Tiny cracks in how the server handled data, potentially allowing an attacker to crash the system.

Input Validation Flaws: Silent doors left ajar where malicious actors could slip in unauthorized commands.

Denial of Service (DoS): Overwhelming the server until it could no longer serve its users.

The real danger wasn't just in the code itself, but in what it connected to. Old Faithful sat on an unpatched SQL Injection vulnerability (CVE-2026-5640) within its shopping portal software, allowing remote attackers to manipulate database queries and steal customer data. Other critical flaws, like CVE-2023-5640, had reached a "Critical" CVSS score of 9.8, meaning the wall was virtually gone.

The story of 5.6.40 is a warning: staying on unsupported software is no longer an option. To survive in a modern landscape of code injection and cryptographic failures, Old Faithful's administrators finally realized they had to let go of the past and upgrade to a supported version like PHP 8.x.

PHP Vulnerabilities: Assessment, Prevention, and Mitigation - Zend

Link 2: The National Vulnerability Database (NVD) Search

For government-grade tracking, use the NVD:

Direct link: https://nvd.nist.gov/vuln/search/results?form_type=Basic&results_type=overview&query=PHP+5.6.40&search_type=all

This link provides JSON and XML feeds, official CVSS scores, and impact metrics.

Key Points About PHP 5.6.40

This version is END OF LIFE (security support ended December 31, 2018)
5.6.40 was the final release of the PHP 5.6 branch
It contains backported security fixes from earlier 5.6.x releases

Subject Clarification: "5640" vs. "5.6.40"

If you are asking about PHP 5.6.40, 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.