USN-3500-1: libXfont vulnerability

Releases

• Ubuntu 17.10
• Ubuntu 17.04
• Ubuntu 16.04 ESM
• Ubuntu 14.04 ESM

Packages

• libxfont - X11 font rasterisation library
• libxfont1 - X11 font rasterisation library
• libxfont2 - X11 font rasterisation library

Details

It was discovered that libXfont incorrectly followed symlinks when opening
font files. A local unprivileged user could use this issue to cause the X
server to access arbitrary files, including special device files.

Update instructions

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

Ubuntu 17.10

• libxfont1 - 1:1.5.2-4ubuntu1.1
• libxfont2 - 1:2.0.1-3ubuntu1.1

Ubuntu 17.04

• libxfont1 - 1:1.5.2-4ubuntu0.2
• libxfont2 - 1:2.0.1-3ubuntu0.2

Ubuntu 16.04

• libxfont1 - 1:1.5.1-1ubuntu0.16.04.4
• libxfont2 - 1:2.0.1-3~ubuntu16.04.3

Ubuntu 14.04

• libxfont1 - 1:1.4.7-1ubuntu0.4

After a standard system update you need to reboot your computer to make
all the necessary changes.

References

• CVE-2017-16611