Arch Linux Security Advisory ASA-201502-11 ========================================== Severity: Medium Date : 2015-02-10 CVE-ID : CVE-2015-0245 Package : xorg-server Type : information leak, denial of service Remote : Yes Link : https://wiki.archlinux.org/index.php/CVE Summary ======= The package xorg-server before version 1.16.4-1 is vulnerable to information leak and denial of service. Resolution ========== Upgrade to 1.16.4-1. # pacman -Syu "xorg-server>=1.16.4-1" The problem has been fixed upstream in version 1.16.4. Workaround ========== None. Description =========== Olivier Fourdan from Red Hat has discovered a protocol handling issue in the way the X server code base handles the XkbSetGeometry request. The issue stems from the server trusting the client to send valid string lengths in the request data. A malicious client with string lengths exceeding the request length can cause the server to copy adjacent memory data into the XKB structs. This data is then available to the client via the XkbGetGeometry request. The data length is at least up to 64k, it is possible to obtain more data by chaining strings, each string length is then determined by whatever happens to be in that 16-bit region of memory. A similarly crafted request can likely cause the X server to crash. Impact ====== A remote attacker is able to use specially crafted XkbSetGeometry requests to obtain adjacent memory data into the XKB structs leading to information leakage or cause the X server to crash resulting in denial of service. References ========== http://www.x.org/wiki/Development/Security/Advisory-2015-02-10/ http://cgit.freedesktop.org/xorg/xserver/commit/?id=20079c https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0255