The Linux kernel through 5.3.13 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. CREATE(Triage):(User=admin) CVE-2019-18660 (https://nvd.nist.gov/vuln/detail/CVE-2019-18660)
