Ubuntu 14.10 USN-2470-1 Critical: Git Remote Code Execution Threat

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 14.10:
  git                             1:2.1.0-1ubuntu0.1

Ubuntu 14.04 LTS:
  git                             1:1.9.1-1ubuntu0.1

Ubuntu 12.04 LTS:
  git                             1:1.7.9.5-1ubuntu0.1

After a standard system update you need to set the core.protectHFS and/or
core.protectNTFS Git configuration variables to "true" if you store Git trees
in HFS+ and/or NTFS filesystems. If you host Git trees, setting the
core.protectHFS, core.protectNTFS, and receive.fsckObjects Git configuration
variables to "true" will cause your Git server to reject objects containing
malicious paths intended to overwrite the Git metadata.