The Linux kernel before 5.1-rc5 allows page->_refcount reference count overflow, with resultant use-after-free issues, if about 140 GiB of RAM exists. This is related to fs/fuse/dev.c, fs/pipe.c, fs/splice.c, include/linux/mm.h, include/linux/pipe_fs_i.h, kernel/trace/trace.c, mm/gup.c, and mm/hugetlb.c. It can occur with FUSE requests.
4.4.0-165.1934.4.0-1095.1064.15.0-1047.49~16.04.14.15.0-1056.614.15.0-1041.434.15.0-60.67~16.04.14.4.0-1059.664.15.0-1022.25~16.04.14.4.0-1123.1324.4.0-1127.135Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:HI:HA:HCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H