Shayan Sadigh discovered a vulnerability in OpenSSH: If PAM support is enabled and the sshd PAM configuration is configured to read userspecified environment variables and the UseLogin option is enabled, a local user may escalate her privileges to root.
In Debian UseLogin is not enabled by default.
For the oldstable distribution (wheezy), this problem has been fixed in version 6.0p1-4+deb7u4.
For the stable distribution (jessie), this problem has been fixed in version 6.7p1-5+deb8u2.
For the unstable distribution (sid), this problem has been fixed in version 1:7.2p2-3.
We recommend that you upgrade your openssh packages.