drupal 8.6.6

Maintenance and security release of the Drupal 8 series.

This release fixes security vulnerabilities. Sites are urged to upgrade immediately after reading the notes below and the security announcement:

• Drupal core - Third Party Libraries - SA-CORE-2019-001
• Drupal core - Arbitrary PHP code execution - SA-CORE-2019-002

No other fixes are included.

Sites on 8.5.x or earlier should update immediately to Drupal 8.5.8 instead, and plan to update to the latest 8.6.x release before May 2019.

Important update information

• The .phar file extension has been added to Drupal's dangerous extensions list, which means that any such file uploaded to a Drupal file field will automatically be converted to a text file (with the .txt extension) to prevent it from being executed. This is similar to how Drupal handles file uploads with a .php extension.

• No changes have been made to the .htaccess, web.config, robots.txt or default settings.php files in this release, so upgrading custom versions of those files is not necessary.

Known issues

Users are reporting seeing a fatal error when updating their sites with Drush. Site owners may be able to run drush updb and either drush cc all or drush cr depending on the version to complete the update. Check the status report afterward to confirm that Drupal has been updated. See #3026386: Drush fatal error after upgrading to 8.6.6, 8.5.9, or 7.62: PHP Fatal error: Uncaught TYPO3\PharStreamWrapper\Exception for details.