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

SAML authentication bypass in GitHub Enterprise

A CRITICAL issue was identified that allows an attacker to bypass SAML authentication by creating a fake response. This could allow the attacker to sign in as any user, including administrators.

The affected supported versions are:

• 2.8.0 - 2.8.5
• 2.7.0 - 2.7.9
• 2.6.0 - 2.6.14
• 2.5.0 - 2.5.19

If you are using SAML as your authentication method, we strongly recommend upgrading your GitHub Enterprise appliance to the latest patch release in your series, GitHub Enterprise 2.8.6, 2.7.10, 2.6.15, or 2.5.20.

Additionally, all existing user sessions should be destroyed:

1. Put your GitHub Enterprise environment in Maintenance Mode.

2. SSH to your primary GitHub Enterprise appliance.

3. Destroy the existing SAML sessions.

   $ echo SAML::Session.destroy_all | ghe-console -y
   

4. Upgrade to the latest patch release in your series, GitHub Enterprise 2.8.6, 2.7.10, 2.6.15, or 2.5.20.

This vulnerability was reported through the GitHub Security Bug Bounty program and we have no evidence that it has been exploited in the wild.

Please contact GitHub Enterprise Support if you have any questions.

Security Fixes

• CRITICAL: Users could bypass SAML authentication and log in as any other user
• Packages have been updated to the latest security versions.

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