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TITLE:
Xen PVFB Shared Framebuffer Processing Vulnerability

SECUNIA ADVISORY ID:
SA30781

VERIFY ADVISORY:
http://secunia.com/advisories/30781/

CRITICAL:
Less critical

IMPACT:
Security Bypass, DoS

WHERE:
Local system

SOFTWARE:
Xen 3.x
http://secunia.com/product/15863/

DESCRIPTION:
A vulnerability has been reported in Xen, which can be exploited by
malicious, local users to cause a DoS (Denial of Service) or
potentially bypass certain security restrictions.

The vulnerability is caused due to an error in the PVFB (Para
Virtualized Frame Buffer) functionality. This can be exploited to
cause a crash or potentially execute arbitrary code in Dom0 via a
specially crafted description for the shared framebuffer.

The vulnerability is reported in version 3.2.1. Other versions may
also be affected.

SOLUTION:
Fixed in the mercurial repository.
http://xenbits.xensource.com/xen-unstable.hg?diff/53195719f762/tools/ioemu/hw/xenfb.c
http://xenbits.xensource.com/xen-unstable.hg?diff/9044705960cb/tools/ioemu/hw/xenfb.c

PROVIDED AND/OR DISCOVERED BY:
Markus Armbruster, Red Hat

ORIGINAL ADVISORY:
http://xenbits.xensource.com/xen-unstable.hg?rev/53195719f762

https://bugzilla.redhat.com/show_bug.cgi?id=443078

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About:
This Advisory was delivered by Secunia as a free service to help
everybody keeping their systems up to date against the latest
vulnerabilities.

Subscribe:
http://secunia.com/secunia_security_advisories/

Definitions: (Criticality, Where etc.)
http://secunia.com/about_secunia_advisories/


Please Note:
Secunia recommends that you verify all advisories you receive by
clicking the link.
Secunia NEVER sends attached files with advisories.
Secunia does not advise people to install third party patches, only
use those supplied by the vendor.

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