CVE-2019-12749

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.

Bugs

• <https://gitlab.freedesktop.org/dbus/dbus/issues/269&gt;