mount.ecryptfs_private.c in eCryptfs-utils does not validate mount destination filesystem types, which allows local users to gain privileges by mounting over a nonstandard filesystem, as demonstrated by /proc/$pid.
{ "ubuntu_priority": "medium", "availability": "No subscription required", "binaries": [ { "binary_name": "ecryptfs-utils", "binary_version": "104-0ubuntu1.14.04.4" }, { "binary_name": "ecryptfs-utils-dbg", "binary_version": "104-0ubuntu1.14.04.4" }, { "binary_name": "ecryptfs-utils-dbgsym", "binary_version": "104-0ubuntu1.14.04.4" }, { "binary_name": "libecryptfs-dev", "binary_version": "104-0ubuntu1.14.04.4" }, { "binary_name": "libecryptfs-dev-dbgsym", "binary_version": "104-0ubuntu1.14.04.4" }, { "binary_name": "libecryptfs0", "binary_version": "104-0ubuntu1.14.04.4" }, { "binary_name": "libecryptfs0-dbgsym", "binary_version": "104-0ubuntu1.14.04.4" }, { "binary_name": "python-ecryptfs", "binary_version": "104-0ubuntu1.14.04.4" }, { "binary_name": "python-ecryptfs-dbgsym", "binary_version": "104-0ubuntu1.14.04.4" } ] }