The Linux kernel before 5.4.1 on powerpc allows Information Exposure because the Spectre-RSB mitigation is not in place for all applicable CPUs, aka CID-39e72bf96f58. This is related to arch/powerpc/kernel/entry_64.S and arch/powerpc/kernel/security.c.
4.4.0-171.2004.4.0-1100.1114.15.0-1057.59~16.04.14.15.0-1066.714.15.0-1052.564.15.0-74.83~16.04.14.10.0-14.16~16.04.14.10.0-19.21~16.04.14.10.0-20.22~16.04.14.10.0-21.23~16.04.14.10.0-22.24~16.04.14.10.0-24.28~16.04.14.10.0-26.30~16.04.14.11.0-13.19~16.04.14.11.0-14.20~16.04.14.13.0-16.19~16.04.3+13 more4.4.0-1064.714.15.0-1031.34~16.04.14.4.0-1127.136Exploitability
AV:LAC:HPR:LUI:NScope
S:UImpact
C:HI:NA:NCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N