An issue was discovered in the Linux kernel through 4.17.10. There is a NULL pointer dereference and panic in hfsplus_lookup() in fs/hfsplus/dir.c when opening a file (that is purportedly a hard link) in an hfs+ filesystem that has malformed catalog data, and is mounted read-only without a metadata directory.
4.4.0-1034.374.4.0-139.165~14.04.14.4.0-139.1654.4.0-1072.824.15.0-1047.49~16.04.14.15.0-1055.604.15.0-1040.42~16.04.14.15.0-58.64~16.04.14.4.0-1037.434.15.0-1021.23~16.04.1Exploitability
AV:LAC:LPR:NUI:RScope
S:UImpact
C:NI:NA:HCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H