The 2.12 series release notes contain important changes in this release series.

Security Fixes

• LOW: It was identified internally that the existence of private repositories could be determined due to the differing error messages of some REST API endpoints. These error messages have been updated to be consistent regardless of a user’s authorization to the repository. No information except for the existence of a private repository would have been exposed due to this issue.

Bug Fixes

• Upgrades to later feature releases were blocked if the new patch release number is lower than the current one.
• Wiki footer options were not shown for read-only users.

Known Issues

• 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.
• 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.
• GitHub Enterprise clustering can not be configured without https.
• Pull request review comments migrated with ghe-migrator are displayed in the wrong order.
• Git LFS, release and issue assets, user profile images, webhooks, or Subversion access may be unavailable if an appliance is restarted after applying the 2.12.5 or greater hotpatch—if this occurs, please contact Enterprise Support for assistance.
• Pages builds fail when TLS is disabled. (updated 2018-04-03)
• On a repository that's been locked for migration using ghe-migrator, project boards are not exported. (updated 2018-05-07)
• Nameid-format matching on SAML response is too strict when value is "unspecified", which can cause an error with the "Another user already owns the account." message if the IdP changes NameID. (updated 2018-06-25)

Thanks!

The GitHub Team