Tobias Stoeckmann discovered that it was possible to trigger an out-of-boundary heap write with the image viewer feh while receiving an IPC message.

For Debian 8 Jessie, this problem has been fixed in version 2.12-1+deb8u1.

We recommend that you upgrade your feh 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