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

Security Fixes

• CRITICAL ImageMagick policies have been updated to address CVE-2016-3714.
• HIGH OpenSSL packages have been updated to address multiple vulnerabilities, including CVE-2016-2105, CVE-2016-2106, CVE-2016-2107, CVE-2016-2108, and CVE-2016-2109.

Remote Code Execution in ImageMagick

Several vulnerabilities in ImageMagick, a package commonly used by web services to process images, have been discovered and disclosed by members of the Mail.ru Security team. One of the vulnerabilities is critical and can lead to remote code execution when processing user submitted images.

Final patches for all the disclosed vulnerabilities within ImageMagick are still pending. This release mitigates the remote code execution vulnerability by implementing the recommended policy to disable the vulnerable ImageMagick coders.

This vulnerability exists in ImageMagick but there is no evidence that it has been exploited on GitHub Enterprise.

We strongly recommend that all GitHub Enterprise customers upgrade their instances as soon as possible.

Mitigation
If you can't immediately upgrade, the issue can be mitigated by implementing the policy changes as follows:

1. SSH to your GitHub Enterprise appliance.

2. Edit the /etc/ImageMagick/policy.xml file:

   sudo vi /etc/ImageMagick/policy.xml
   

3. Disable the vulnerable coders by replacing the <policymap> section with:

   <policymap>
     <policy domain="coder" rights="none" pattern="EPHEMERAL" />
     <policy domain="coder" rights="none" pattern="URL" />
     <policy domain="coder" rights="none" pattern="HTTPS" />
     <policy domain="coder" rights="none" pattern="MVG" />
     <policy domain="coder" rights="none" pattern="MSL" />
   </policymap>
   

There is no need to reboot or restart any services; the changes will take effect immediately.

Please contact GitHub Enterprise Support if you have any questions.

Bug Fixes

• Memcached didn't log warnings or errors.
• Harmless empty lines were added to the admin user's authorized_keys file every time the configuration was saved.
• The find command was missing in the default pre-receive hook environment.

Known Issues

• HIGH Release assets from a public repository can be accessed by unauthenticated users in private mode. (updated 2016-05-27)
• 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.
• Custom messages within the Admin Center are not disabled when SAML authentication is used, even though they have no effect since the SAML server is responsible for displaying the relevant messages to users.
• The custom messages Markdown editor in the Admin Center includes buttons for non-applicable functionality.
• Background jobs in the languages queue aren't run. This causes repository language statistics to be inaccurate.
• Repository push logs don't record whether a push was forced. (updated 2016-05-13)
• svn checkout may timeout while the repository data cache is being built. In most cases, subsequent svn checkout attempts will succeed. (updated 2016-05-24)
• Git LFS tracked files uploaded through the web interface are incorrectly added directly to the repository. (updated 2016-05-24)
• Migration data exported from GitHub Enterprise with ghe-migrator does not include issue file attachments, which may cause imports to another server to fail. (updated 2016-06-09)
• GitHub Enterprise clustering can not be configured without https. (updated 2016-08-01)
• Console text is difficult to read on OpenStack KVM. (updated 2016-08-03)
• 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