Linux kernel is vulnerable to a heap-based buffer overflow in the fs/ext4/xattr.c:ext4_xattr_set_entry() function. An attacker could exploit this by operating on a mounted crafted ext4 image.
https://usn.ubuntu.com/3752-3/
https://usn.ubuntu.com/3752-2/
https://usn.ubuntu.com/3752-1/
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10840