Arch Linux Security Advisory ASA-201710-10 ========================================== Severity: Medium Date : 2017-10-08 CVE-ID : CVE-2017-13721 CVE-2017-13723 Package : xorg-server Type : multiple issues Remote : No Link : https://security.archlinux.org/AVG-432 Summary ======= The package xorg-server before version 1.19.4-1 is vulnerable to multiple issues including arbitrary code execution and denial of service. Resolution ========== Upgrade to 1.19.4-1. # pacman -Syu "xorg-server>=1.19.4-1" The problems have been fixed upstream in version 1.19.4. Workaround ========== None. Description =========== - CVE-2017-13721 (denial of service) A denial of service vulnerability was found in xorg-server in the ProcShmCreateSegment function due to a missing shmseg resource ids validation. A passed shmseg resource id may belong to a non-existing client and abort X server with FatalError "client not in use", or overwrite existing segment of another existing client. - CVE-2017-13723 (arbitrary code execution) A stack buffer overflow was found in xkbtext.c, which didn't handle xkb formatted string output safely due to a single shared static buffer. The fix introduces a ring of resizable buffers to avoid problems when strings end up longer than anticipated. This vulnerability may potentially lead to privilege escalation when the xorg-server is running with root privileges. Impact ====== A local attacker is able to crash the xorg-server process leading to denial of service or possibly elevate privileges when the xorg-server is running with root privileges. References ========== https://lists.x.org/archives/xorg-announce/2017-October/002808.html https://cgit.freedesktop.org/xorg/xserver/commit/?id=b95f25af141d33a65f6f821... https://cgit.freedesktop.org/xorg/xserver/commit/?id=94f11ca5cf011ef123bd222... https://security.archlinux.org/CVE-2017-13721 https://security.archlinux.org/CVE-2017-13723