Affecting dbus package, versions debian:10: <1.12.16-1 || debian:8: <1.8.22-0+deb8u2 || debian:9: <1.10.28-0+deb9u1 || debian:unstable: <1.12.16-1 || ubuntu:12.04: <1.4.18-1ubuntu1.9 || ubuntu:14.04: <1.6.18-0ubuntu4.5+esm1 || ubuntu:16.04: <1.10.6-1ubuntu3.4 || ubuntu:18.04: <1.12.2-1ubuntu1.1 || ubuntu:18.10: <1.12.10-1ubuntu2.1
dbus before 1.10.28, 1.12.x before 1.12.16, and 1.13.x before 1.13.12, as used in DBusServer in Canonical Upstart in Ubuntu 14.04 (and in some, less common, uses of dbus-daemon), allows cookie spoofing because of symlink mishandling in the reference implementation of DBUS_COOKIE_SHA1 in the libdbus library. (This only affects the DBUS_COOKIE_SHA1 authentication mechanism.) A malicious client with write access to its own home directory could manipulate a ~/.dbus-keyrings symlink to cause a DBusServer with a different uid to read and write in unintended locations. In the worst case, this could result in the DBusServer reusing a cookie that is known to the malicious client, and treating that cookie as evidence that a subsequent client connection came from an attacker-chosen uid, allowing authentication bypass.