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

Security Fixes

• CRITICAL In versions 2.6.0 through 2.6.5 of GitHub Enterprise, a CAS authenticated user may log in as another user if they have full control of the login value registered with the external authentication provider. While this issue only affects specific installations, we have released this as a CRITICAL issue given its impact when external authentication configurations allow user control of registered logins.
• LOW The permissions on rbenv, used by many components of GitHub Enterprise, have been tightened.
• Packages have been updated to the latest security versions.

Bug Fixes

• Built Pages sites on a cluster node became inaccessible if the database master role was migrated to the node.
• The schema for requests to and responses from the LFS API has been relaxed to allow additional properties. This will allow the API to be extended in the future.
• Organizations could be suspended using the ghe-user-suspend command.
• Adding a new node to a cluster would fail if another node was unavailable.
• Updates to user avatars may not have been visible for up to five minutes on clustered installations.

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.
• The initial import of the VMware OVA image may fail when deployed via vCenter Server 6.0 or 6.5. The import will succeed when performed directly on an ESXi host. (updated 2017-02-23)
• Git LFS objects may take up to an hour to replicate in a High Availability configuration. (updated 2017-02-23)

Thanks!

The GitHub Team