RHSA-2011:1834 - Security Advisory

Topic

Updated libXfont packages that fix one security issue are now available for
Red Hat Enterprise Linux 5.6 Extended Update Support.

The Red Hat Security Response Team has rated this update as having
important security impact. A Common Vulnerability Scoring System (CVSS)
base score, which gives a detailed severity rating, is available from the
CVE link in the References section.

Description

The libXfont packages provide the X.Org libXfont runtime library. X.Org is
an open source implementation of the X Window System.

A buffer overflow flaw was found in the way the libXfont library, used by
the X.Org server, handled malformed font files compressed using UNIX
compress. A malicious, local user could exploit this issue to potentially
execute arbitrary code with the privileges of the X.Org server.
(CVE-2011-2895)

Users of libXfont should upgrade to these updated packages, which contain a
backported patch to resolve this issue. All running X.Org server instances
must be restarted for the update to take effect.

Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 ia64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 i386
• Red Hat Enterprise Linux Server - AUS 5.6 x86_64
• Red Hat Enterprise Linux Server - AUS 5.6 ia64
• Red Hat Enterprise Linux Server - AUS 5.6 i386
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 5.6 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 5.6 ppc
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.6 i386

Fixes

• BZ - 725760 - CVE-2011-2895 libXfont: LZW decompression heap corruption / infinite loop
• BZ - 727624 - CVE-2011-2895 BSD compress LZW decoder buffer overflow

CVEs

• CVE-2011-2895

References

• https://access.redhat.com/security/updates/classification/#important