7.5 - RHSA-2015:2233

Problem Description:

Updated tigervnc packages that fix two security issues, several bugs, and add various enhancements are now available for Red Hat Enterprise Linux 7.

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Client (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Client Optional (v. 7) - noarch, x86_64 Red Hat Enterprise Linux ComputeNode (v. 7) - noarch, x86_64 Red Hat Enterprise Linux ComputeNode Optional (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Server (v. 7) - aarch64, noarch, ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 7) - aarch64, noarch, ppc64, ppc64le, x86_64 Red Hat Enterprise Linux Workstation (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 7) - noarch, x86_64

3. Description:

Virtual Network Computing (VNC) is a remote display system which allows users to view a computing desktop environment not only on the machine where it is running, but from anywhere on the Internet and from a wide variety of machine architectures. TigerVNC is a suite of VNC servers and clients. The tigervnc packages contain a client which allows users to connect to other desktops running a VNC server.

An integer overflow flaw, leading to a heap-based buffer overflow, was found in the way TigerVNC handled screen sizes. A malicious VNC server could use this flaw to cause a client to crash or, potentially, execute arbitrary code on the client. (CVE-2014-8240)

A NULL pointer dereference flaw was found in TigerVNC's XRegion. A malicious VNC server could use this flaw to cause a client to crash. (CVE-2014-8241)

The tigervnc packages have been upgraded to upstream version 1.3.1, which provides a number of bug fixes and enhancements over the previous version. (BZ#1199453)

This update also fixes the following bug:

* The position of the mouse cursor in the VNC session was not correctly communicated to the VNC viewer, resulting in cursor misplacement. The method of displaying the remote cursor has been changed, and cursor movements on the VNC server are now accurately reflected on the VNC client. (BZ#1100661)

All tigervnc users are advised to upgrade to these updated packages, which correct these issues and add these enhancements.

4. Solution:

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

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

5. Bugs fixed (https://bugzilla.redhat.com/):

1072733 - vnc black screen and error 'XRequest.130: BadValue (integer parameter out of range for operation) 0x400' 1119640 - VNC-EXTENSION missed on Xorg server regeneration 1151307 - CVE-2014-8240 tigervnc: integer overflow flaw, leading to a heap-based buffer overflow in screen size handling 1151312 - CVE-2014-8241 tigervnc: NULL pointer dereference flaw in XRegion 1162722 - tigervnc-server has no IPV6 support 1181287 - gnome 3 session inside vncserver changes initial resolution instead of using what was specified from "-geometry 1194898 - Rebuild tigervnc against rebased xserver in 7.2 1195266 - The display number is not required in the file name for VNC 1199437 - Enable Xinerama extension 1199453 - Re-base to tigervnc-1.3.x