The 2.6 series release notes contain important changes in this release series.

Security Fixes

• LOW: Detect and reject any Git content that shows evidence of being part of a SHA-1 collision attack.
• Packages have been updated to the latest security versions.

Bug Fixes

• The /trending page could incorrectly display a Sign up for free button.
• The total number of organizations was incorrect because the count included trusted OAuth applications.
• Administrators couldn't restore deleted LFS objects.

Upcoming deprecation of GitHub Enterprise 2.6

GitHub Enterprise 2.6 will be deprecated as of April 26, 2017. That means that no patch releases will be made, even for critical security issues, after this date. For better performance, improved security, and new features, upgrade to the newest version of GitHub Enterprise as soon as possible.

Known Issues

• We incorrectly redirect to the dashboard if you accessed GitHub Enterprise using an alias while in private mode. This might happen if you set a fully qualified domain name but the subdomain resolves correctly.
• Images uploaded to issues save with an absolute URL, so they can be broken if the hostname changes.
• On a freshly set up GitHub Enterprise without any users, an attacker could create the first admin user.
• Custom firewall rules aren't maintained during an upgrade.
• Enqueued background jobs are sometimes not purged when a repository is deleted.
• On instances upgraded from 2.3 and earlier, restoring a protected branch archived whilst running 2.3, will not restore all the settings correctly. This does not affect new instances or protected branches archived on later releases.
• Editing custom messages in the Admin Center doesn't provide emoji suggestions.
• Native emoji are lost when saving custom messages in the Admin Center.
• Repository push logs don't record whether a push was forced.
• svn checkout may timeout while the repository data cache is being built. In most cases, subsequent svn checkout attempts will succeed.
• Git LFS tracked files uploaded through the web interface are incorrectly added directly to the repository.
• Uploading PNG images with through the web interface can fail with the error 'Something went really wrong, and we can't process that file.'
• GitHub Enterprise clustering can not be configured without https.
• Console text is difficult to read on OpenStack KVM.
• Deleting a search index doesn't delete all associated metadata, which are then incorrectly reused if a new search index is created. This causes search index repair jobs to be reported as finished in the site admin when they were not. (updated 2017-03-30)
• An issue or pull request comment containing the string "User-Agent: GitHub-Hookshot" incorrectly triggers a firewall rule and causes an internal server error on several pages, including the author's profile page. (updated 2017-03-30)

Thanks!

The GitHub Team