In the Linux kernel before 4.20.14, expand_downwards in mm/mmap.c lacks a check for the mmap minimum address, which makes it easier for attackers to exploit kernel NULL pointer dereferences on non-SMAP platforms. This is related to a capability check for the wrong task. Upstream fix: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0a1d52994d440e21def1c2174932410b4f2a98a1
Fix in 4.9.162, 4.14.105, 4.19.27, 4.20.14, 5.0.