WordPress Release: 4.6.22

TL;DR

WordPress 4.6.22 is a security and maintenance release that addresses several important vulnerabilities and improves code quality. This update focuses on enhancing data sanitization in queries, fixing potential security issues with unserialization, improving date/time handling to prevent race conditions, and ensuring proper character encoding in post slugs. All WordPress 4.6 users should update immediately to protect their sites from potential security risks.

Highlight of the Release

• Enhanced security through improved sanitization in WP_Tax_Query and WP_Meta_Query
• Reduced security risk by avoiding unnecessary use of unserialize()
• Fixed encoding of ASCII characters in post slugs
• Improved date/time handling to prevent race conditions in tests

Migration Guide

No specific migration steps are required for this update. This is a standard security and maintenance release that should be applied through the normal WordPress update process.

To update:

1. Back up your website files and database
2. Update through the WordPress admin dashboard or download the update from wordpress.org
3. Test your website functionality after updating

No changes to themes or plugins should be necessary as a result of this update.

Upgrade Recommendations

Immediate Update Recommended

This release contains important security fixes that protect your WordPress site from potential vulnerabilities. All users running WordPress 4.6.x should update to version 4.6.22 immediately.

While WordPress 4.6 is an older branch and no longer receives regular updates, this security release demonstrates the WordPress team's commitment to patching critical security issues even in legacy versions. However, for the best security and features, users should consider upgrading to the latest major WordPress version if possible.

Bug Fixes

Date/Time Handling

• Fixed potential race conditions in get_gmt_from_date() tests by implementing delta comparison instead of exact time matching

Post Slug Encoding

• Fixed incorrect encoding of ASCII characters in post slugs, ensuring proper URL formatting and consistency

New Features

No new features were introduced in this maintenance and security release. WordPress 4.6.22 focuses on security improvements and bug fixes to the existing codebase.

Security Updates

Query Sanitization

• Improved sanitization within WP_Tax_Query to prevent potential SQL injection vulnerabilities
• Enhanced sanitization within WP_Meta_Query to strengthen security of database queries

Unserialization Security

• Reduced security risk by avoiding unnecessary use of unserialize() during upgrade and installation processes, which helps prevent potential PHP object injection attacks

Performance Improvements

No specific performance improvements were highlighted in this release. The changes were primarily focused on security enhancements and bug fixes rather than performance optimizations.

Impact Summary

WordPress 4.6.22 is primarily a security-focused release that addresses several potential vulnerabilities in the WordPress core. By improving sanitization in database queries (WP_Tax_Query and WP_Meta_Query), reducing unsafe unserialization practices, and fixing character encoding issues, this update significantly enhances the security posture of WordPress 4.6 installations.

The changes are largely invisible to end users but provide important protections against potential attacks. Site administrators should prioritize this update to safeguard their websites against security threats. While this is a maintenance release for an older branch of WordPress, the security improvements are substantial enough to warrant immediate attention.

For developers, the changes to query sanitization and serialization handling may be relevant when working with custom code that interacts with these WordPress core components. The improvements to date/time handling in tests also help ensure more reliable testing environments.