CVE-2016-0728 on Ubuntu 14.04 LTS (trusty) - high.
Description:
The join_session_keyring function in security/keys/process_keys.c in the Linux kernel before 4.4.1 mishandles object references in a certain error case, which allows local users to gain privileges or cause a denial of service (integer overflow and use-after-free) via crafted keyctl commands. Yevgeny Pats discovered that the session keyring implementation in the Linux kernel did not properly reference count when joining an existing session keyring. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code with administrative privileges.