In the Linux kernel 5.0.21 and 5.3.11, mounting a crafted btrfs filesystem image, performing some operations, and then making a syncfs system call can lead to a use-after-free in try_merge_free_space in fs/btrfs/free-space-cache.c because the pointer to a left data structure can be the same as the pointer to a right data structure.
4.4.0-190.2204.4.0-1114.1274.15.0-1085.90~16.04.14.15.0-1098.109~16.04.14.15.0-1086.98~16.04.14.15.0-120.122~16.04.14.10.0-14.16~16.04.14.10.0-19.21~16.04.14.10.0-20.22~16.04.14.10.0-21.23~16.04.14.10.0-22.24~16.04.14.10.0-24.28~16.04.14.10.0-26.30~16.04.14.11.0-13.19~16.04.14.11.0-14.20~16.04.14.13.0-16.19~16.04.3+13 more4.4.0-1080.874.15.0-1056.61~16.04.14.4.0-1139.148Exploitability
AV:LAC:LPR:NUI:RScope
S:UImpact
C:HI:HA:HCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H