Integer overflow in the ProcDRI2GetBuffers function in the DRI2 extension in X.Org Server (aka xserver and xorg-server) 1.7.0 through 1.16.x before 1.16.3 allows remote authenticated users to cause a denial of service (crash) or possibly execute arbitrary code via a crafted request, which triggers an out-of-bounds read or write.
https://security.gentoo.org/glsa/201504-06
http://www.x.org/wiki/Development/Security/Advisory-2014-12-09/
http://www.securityfocus.com/bid/71601
http://www.oracle.com/technetwork/topics/security/bulletinjan2015-2370101.html
http://www.debian.org/security/2014/dsa-3095
http://secunia.com/advisories/62292