Multiple race conditions in the Advanced Union Filesystem (aufs) aufs3-mmap.patch and aufs4-mmap.patch patches for the Linux kernel 3.x and 4.x allow local users to cause a denial of service (use-after-free and BUG) or possibly gain privileges via a (1) madvise or (2) msync system call, related to mm/madvise.c and mm/msync.c. Ben Hutchings discovered that the Advanced Union Filesystem (aufs) for the Linux kernel did not correctly handle references of memory mapped files from an aufs mount. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code with administrative privileges.