Felix Wilhelm of Google Project Zero discovered a flaw in git, a fast, scalable, distributed revision control system. With a crafted URL that contains a newline, the credential helper machinery can be fooled to return credential information for a wrong host.

For Debian 8 Jessie, this problem has been fixed in version 1:2.1.4-2.1+deb8u9.

We recommend that you upgrade your git packages.

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS