Integer underflow in the xTrapezoidValid macro in render/picture.h in X.Org allows context-dependent attackers to cause a denial of service (crash) via a negative bottom value.

References

• https://nvd.nist.gov/vuln/detail/CVE-2013-6424
• https://bugs.freedesktop.org/show_bug.cgi?id=67484
• https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1197921
• https://security.gentoo.org/glsa/201701-64
• https://security.gentoo.org/glsa/201710-30
• http://lists.opensuse.org/opensuse-updates/2013-12/msg00127.html
• http://lists.x.org/archives/xorg-devel/2013-October/037996.html
• http://rhn.redhat.com/errata/RHSA-2013-1868.html
• http://www.debian.org/security/2013/dsa-2822
• http://www.openwall.com/lists/oss-security/2013/12/03/8
• http://www.openwall.com/lists/oss-security/2013/12/04/8
• http://www.ubuntu.com/usn/USN-2500-1
• https://access.redhat.com/errata/RHSA-2013:1868
• https://access.redhat.com/security/cve/CVE-2013-6424
• https://bugzilla.redhat.com/show_bug.cgi?id=1037984