RHSA-2015:0113 - Security Advisory

Topic

Updated libvncserver packages that fix two security issues are now
available for Red Hat Enterprise Linux 6.5 Extended Update Support.

Red Hat Product Security has rated this update as having Moderate security
impact. Common Vulnerability Scoring System (CVSS) base scores, which give
detailed severity ratings, are available for each vulnerability from the
CVE links in the References section.

Description

LibVNCServer is a library that allows for easy creation of VNC server or
client functionality.

An integer overflow flaw, leading to a heap-based buffer overflow, was
found in the way screen sizes were handled by LibVNCServer. A malicious VNC
server could use this flaw to cause a client to crash or, potentially,
execute arbitrary code in the client. (CVE-2014-6051)

Two stack-based buffer overflow flaws were found in the way LibVNCServer
handled file transfers. A remote attacker could use this flaw to crash the
VNC server using a malicious VNC client. (CVE-2014-6055)

Red Hat would like to thank oCERT for reporting these issues. oCERT
acknowledges Nicolas Ruff as the original reporter.

All libvncserver users are advised to upgrade to these updated packages,
which contain backported patches to correct these issues. All running
applications linked against libvncserver must be restarted for this 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/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 i386
• Red Hat Enterprise Linux Server - AUS 6.5 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.5 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.5 ppc64
• Red Hat Enterprise Linux Server - TUS 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 i386

Fixes

• BZ - 1144287 - CVE-2014-6051 libvncserver: integer overflow flaw, leading to a heap-based buffer overflow in screen size handling
• BZ - 1144293 - CVE-2014-6055 libvncserver: server stacked-based buffer overflow flaws in file transfer handling

CVEs

• CVE-2014-6055
• CVE-2014-6051

References

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